Mooseman
Moderator
Could just be semantics. The sensors do send "information" or data to the PCM albeit electrically.
SOLVED! All modules failing randomly or different starting point?
- Thread starter Elizabetty
- Start date
The difference is analog vs. digital. Sensor data is analog, typically voltage, whereas serial data is high/low (1/0) and is structured (header, sender, receiver, data bytes, checksum) per a specific protocol (Class 2 Serial, CanBus). Sensor lines feed back to specific pins on the PCM (e.g. oil pressure, fuel level, etc.) whereas data signals share a common data bus.
In the harness right next to the fuse box under the hood, there is a highly suspicious yellow wire that seems to be crusted in a block of dirt that was cleaned off with electrical cleaner but it doesn't look right. I'm in the process of going through the diagrams you guys supplied to see what that is responsible for. I'm still learning about when a bad wire means you need a brand new harness versus if it's possible to reset that wire in the connection which is my fear that you can't pin it again. I'm not sure how to explain that correctly but if it can't be pulled out stripped and set again, then maybe I have a continuous problem. I have attached a photo.
Attachments
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Mooseman
Moderator
That is the main underhood harness connector. Basically everything from under the hood connects to the rest of the truck. Don't know what that particular yellow wire if for but it does look crusty. Might as well check all of them.
Another way of thinking here.... A failing sensor or the like will not ever set a "Uxxxx code" to be read by a scanner. Just in case anyone is thinking a leaking CPAS can cause a communications DTC to set and be read by a scantool.
It might take me a while to find where I have that diagram but I can say that the light blue wire directly below that yellow wire is the serial data wire from the EBCM. It runs from the EBCM under the drivers seat area beneath the vehicle through that connector and into the underdash area where it connects to the SP205 serial data splice pack.
I know this because that is where I have accessed the serial data system to unlock my doors with a bluetooth dongle in a "proof of concept" experiment I have done a time or two.
Look really close, looks like yellow/black. Vehicle speed signal, circuit 1827, pin C2.
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I'm finally getting around to tackling a potential grounding issue per a bulletin released years ago regarding the splice pack on the passenger side under the center console. I've pulled the screw and pulled the carpeted part back but I can't see or access the bolt to make sure there's no carpet underneath it per the bulletin. Based on some issues I have, and from explanations you guys have given me, it's worth taking a look at but without taking out the center console, I'm not sure how to move forward. The only other screw I see would be on the driver side carpeted piece. I've looked on YouTube for how to remove the console but can't find anything that quite matches what I have and I don't want to break any plastic. Are there similar makes and models you may be aware of that would have a similar removal process? I'm currently waiting on a manual that will show me some of the stuff going forward but in the meantime, I'm asking here. I believe it was this thread that had a YouTube video shared with me where he gets in there with only removing that one screw, but there seems to be a lot more play in his wiring underneath there and mine is tight tight so the connection is tight to the floor and I can't move anything to look at that bolt.
Mooseman
Moderator
Okay so I don't know if I should break this incredibly long thread out into new ones or continue here since it has to do with the electrical issue I'm working on. Please direct me if you'd like to shut this down and have me start over with separate threads.
Using a test light, I have determined I have shorts in multiple areas.
Under the hood fuse box:
8 ATC 25a
13 Cigar 20a
24 IPC/DIC 10a
31 TBC 1 10a
Rear fuse box:
41 Radio 15a
06 LGM/DSM 10a
10 DDM 10a
12 PDM 10a
I have been looking through the diagrams that have been shared with me in this and other threads. I have additional grounds that are hard to get to on the engine block that I know I need to check. I believe one of them is g108.
In the meantime, in order to close out some of these short circuits and not cause battery drain issues or charging issues which I'm currently seeing through corrosion that appears after cleaning terminals, are any of these fuses safe to remove and still drive the vehicle? Obviously radio would be safe and doors could be a pain, but shouldn't be a problem. If fuse 8 is removed, would that allow the vehicle to drive and force it to be in 2hi or would I have driveability problems? I don't want to cause any damage. If it is left in, what type of problems would I expect? Would it simply be a problem from changing from 2hi into a4wd and 4x4 or would there be confusion in the modules while driving causing the vehicle to make those changes on its own? I can't entirely trust what the dash says because of course I have a short in that circuit too.
Using a test light, I have determined I have shorts in multiple areas.
Under the hood fuse box:
8 ATC 25a
13 Cigar 20a
24 IPC/DIC 10a
31 TBC 1 10a
Rear fuse box:
41 Radio 15a
06 LGM/DSM 10a
10 DDM 10a
12 PDM 10a
I have been looking through the diagrams that have been shared with me in this and other threads. I have additional grounds that are hard to get to on the engine block that I know I need to check. I believe one of them is g108.
In the meantime, in order to close out some of these short circuits and not cause battery drain issues or charging issues which I'm currently seeing through corrosion that appears after cleaning terminals, are any of these fuses safe to remove and still drive the vehicle? Obviously radio would be safe and doors could be a pain, but shouldn't be a problem. If fuse 8 is removed, would that allow the vehicle to drive and force it to be in 2hi or would I have driveability problems? I don't want to cause any damage. If it is left in, what type of problems would I expect? Would it simply be a problem from changing from 2hi into a4wd and 4x4 or would there be confusion in the modules while driving causing the vehicle to make those changes on its own? I can't entirely trust what the dash says because of course I have a short in that circuit too.
Well here's hoping I wasn't pointed in the wrong direction....
I was sold a test light and given a set of instructions by O'Reilly's. They had me disconnect the negative battery terminal, clamp the test light to the battery and touch the probe to the bolted connector (side post battery). He showed me how my light stayed on and told me to go home and remove fuses until I found the one that made the light go out. I actually did the test backwards, and had the fuses out while cleaning up the box and as I put them in, I noted the ones that made the light come on. Same concept he showed me but reverse order. For example, the main fuse box had all the fuses and relays pulled. I started putting the fuses back and the light stayed off. When I got to fuse number 8, the light came on. I removed it, continued putting my fuses back in and came across another that made the light come on so I jotted it down, removed it, continued. I figured there must have been some accuracy to the test because the liftgate module was one of the initial things discussed in this thread I believe and that happened to be one of the fuses in the rear box that turned the light on. I don't have full radio function and that was another fuse turning the light on when in. I also had a flickering dash light at one point about service four-wheel drive so that made sense that the automatic transfer case fuse was noted.
It was explained to me that once I identified where the light went out when pulled (or turned on when put in in my case), that would be the wiring I would need to follow and find my problem if there was a frayed wire etc, as well as check the corresponding ground. However, instead of finding one to trace, I found eight.
I'm having a hell of a time removing some badly rusted body ground connections I was working on but I know I have to do it. I'm trying to understand how I can eliminate any problems from progressing (IE: wire melting) when it comes to basically killing an unnecessary circuit by pulling the fuse. My hope was if I pull the fuse, no activity would be attempting to happen through the liftgate module for example, and that's one less "active short" that may fry something. I'd much rather fix a ground or repair wire then have to do that and replace the module that may get damaged (if that can happen).
I am a couple hundred pages into one of the manuals I got my hands on but I'm still very green.
I was sold a test light and given a set of instructions by O'Reilly's. They had me disconnect the negative battery terminal, clamp the test light to the battery and touch the probe to the bolted connector (side post battery). He showed me how my light stayed on and told me to go home and remove fuses until I found the one that made the light go out. I actually did the test backwards, and had the fuses out while cleaning up the box and as I put them in, I noted the ones that made the light come on. Same concept he showed me but reverse order. For example, the main fuse box had all the fuses and relays pulled. I started putting the fuses back and the light stayed off. When I got to fuse number 8, the light came on. I removed it, continued putting my fuses back in and came across another that made the light come on so I jotted it down, removed it, continued. I figured there must have been some accuracy to the test because the liftgate module was one of the initial things discussed in this thread I believe and that happened to be one of the fuses in the rear box that turned the light on. I don't have full radio function and that was another fuse turning the light on when in. I also had a flickering dash light at one point about service four-wheel drive so that made sense that the automatic transfer case fuse was noted.
It was explained to me that once I identified where the light went out when pulled (or turned on when put in in my case), that would be the wiring I would need to follow and find my problem if there was a frayed wire etc, as well as check the corresponding ground. However, instead of finding one to trace, I found eight.
I'm having a hell of a time removing some badly rusted body ground connections I was working on but I know I have to do it. I'm trying to understand how I can eliminate any problems from progressing (IE: wire melting) when it comes to basically killing an unnecessary circuit by pulling the fuse. My hope was if I pull the fuse, no activity would be attempting to happen through the liftgate module for example, and that's one less "active short" that may fry something. I'd much rather fix a ground or repair wire then have to do that and replace the module that may get damaged (if that can happen).
I am a couple hundred pages into one of the manuals I got my hands on but I'm still very green.
Damn it I just found something. The 125 amp fuse has a nice bright silver connection on one end, but underneath the other end, about half of it is discolored dark brown. If replacing that solves problems, I will be happy. No amount of cleaning that contact point changes anything. It almost looks burnt to be honest.
Mooseman
Moderator
I don't know if they were taking you for a ride but I have never heard of using a test light like that. The usual way is to put the clip end on a good ground and then test each circuit or fuse for power with the key on. The fuses you test each post where you can see a bit of the metal on top of it. If you get power on both posts with the fuse in, the fuse is good. If some of them don't light at all, it could be a circuit that doesn't come on until that function is turned on, like the wipers. The 125A megafuse would be tested the same way.
Shorts would simply cause the fuse to blow and you would investigate THAT circuit alone.
Shorts would simply cause the fuse to blow and you would investigate THAT circuit alone.
The light lit up when you put #8 fuse in because that fuse powers a control module, the TCCM. There is no switch that turns it off, it is supposed to have power always. Same with a handfull of other modules like the radio and pretty much every other fuse you listed.
Most of these will power up when you put their fuse in and will remain active for a while, like ten minutes or so maybe. Then they go into a sleep mode of sorts. They are not "off" just inactive, waiting for a signal from the BCM or some other module to send a wake up message. A door module can send a wakeup message when first opened for example.
If you had waited long enough after putting in fuse 8 the test light would likely have gotten very dim suddenly after the TCCM went back to sleep mode.
Anything that completes an unswitched control module circuit will make a test light come on when hooked up like they showed you.
I have been tracing wires between all different points and I found some poor shape wires as well as very bad ground connections. I have repaired harnesses and scrubbed up ground points after of course completely busting a bolt when trying to unscrew it but I got it done. The worst one happened to be one you guys told me about under the driver's side front door on the frame. I'm glad I handled it. The ground that is confusing me right now is g302 located on the b pillar. Is that a ground that has to repaired, if needed, by taking the whole side of the car apart? Lol I have the image supplied here but how is it accessed? I'd love to hear that I simply take off something on the inside to access the metal on the outside but my fear is that it's much more complicated. How do I get to it?
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- Jul 22, 2015
- 2,724
If you can get to the other end of the connection, you can attach to a new ground. 'Ground is ground', provided you have a good ground. (there's exceptions to this, but for this vehicle / purpose, it's valid.)
That means that any paint / primer on the surface you attach to is removed, down to bare metal. Use a flat screwdriver or scratch awl to get the paint off. You can repaint over it afterward, if desired.
Need to make a hole for the bolt / screw to fasten the ground wire down with? No problem. Just make sure the wire is fastened securely to bare metal, and you should be set.
I'll have to look up the info / diagram on g302 to be any more specific on how much potential disassembly you'll be looking at. Will post back if I find that info.
Note: If you've got a plastic piece covering the B-pillar, and don't see exposed screw heads... usually, those can be removed with a trim tool (or even with your bare hands, provided you know where the clips underneath are generally located). Use gloves if needed.
(on edit): Ok, I found one diagram online. Looks like you've got a top piece on that B-pillar, probably a second one that is overlapped by the top one, and then maybe the trim on the doorsill.
All show clips as the fastener type. The only thing you should then need to look out for is if a seat belt fastens at the top of the pillar--if so, there'll be a torx bolt underneath the cover (pops off easily).
If that's the case, you'll need to get the right size torx head socket (I think it's a T20, from when I took off the ones at the rear corner (D-pillar)). It'll also take a good bit of strength to get it loose, so put a length of pipe, etc., on the end of your ratchet. IIRC, GM uses a little threadlocker on those bolts.
If you don't have to worry about a seatbelt attachment, then things should be fairly easy. Just trace which trim piece is on top of which. At the bottom, you may be able to just pull out enough of the panel where you can reach in and unscrew the ground wire (or clip it off and relocate it, if it's really tight back there and you'd rather not bother). Again, gloves help, if you don't want the plastic to scrape off your skin while you're rubbing against the edges. If you can't see the screw at all, but can feel it... it'll be a phillips for sure; likely a #2 (PH 2). Make sure it's snug before you start turning, lest you strip it (and then you get to cut / relocate the wire anyway, as a result).
If you go for removal of the back panel in it's entirety... there will be screws & bolts to get into. Mine is the XL / EXT, and the panels are different. But there will be screws & bolts on yours, as well.
That means that any paint / primer on the surface you attach to is removed, down to bare metal. Use a flat screwdriver or scratch awl to get the paint off. You can repaint over it afterward, if desired.
Need to make a hole for the bolt / screw to fasten the ground wire down with? No problem. Just make sure the wire is fastened securely to bare metal, and you should be set.
I'll have to look up the info / diagram on g302 to be any more specific on how much potential disassembly you'll be looking at. Will post back if I find that info.
Note: If you've got a plastic piece covering the B-pillar, and don't see exposed screw heads... usually, those can be removed with a trim tool (or even with your bare hands, provided you know where the clips underneath are generally located). Use gloves if needed.
(on edit): Ok, I found one diagram online. Looks like you've got a top piece on that B-pillar, probably a second one that is overlapped by the top one, and then maybe the trim on the doorsill.
All show clips as the fastener type. The only thing you should then need to look out for is if a seat belt fastens at the top of the pillar--if so, there'll be a torx bolt underneath the cover (pops off easily).
If that's the case, you'll need to get the right size torx head socket (I think it's a T20, from when I took off the ones at the rear corner (D-pillar)). It'll also take a good bit of strength to get it loose, so put a length of pipe, etc., on the end of your ratchet. IIRC, GM uses a little threadlocker on those bolts.
If you don't have to worry about a seatbelt attachment, then things should be fairly easy. Just trace which trim piece is on top of which. At the bottom, you may be able to just pull out enough of the panel where you can reach in and unscrew the ground wire (or clip it off and relocate it, if it's really tight back there and you'd rather not bother). Again, gloves help, if you don't want the plastic to scrape off your skin while you're rubbing against the edges. If you can't see the screw at all, but can feel it... it'll be a phillips for sure; likely a #2 (PH 2). Make sure it's snug before you start turning, lest you strip it (and then you get to cut / relocate the wire anyway, as a result).
If you go for removal of the back panel in it's entirety... there will be screws & bolts to get into. Mine is the XL / EXT, and the panels are different. But there will be screws & bolts on yours, as well.
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It took a while but I have read thru this thread, especially after my problems today with the same rig as @Elizabetty has and is in my signature. As a member of the Tahoe/Yukon Forum, I am very familiar with the ground problems this vintage of GM rigs have. It is especially prevalent in states where salt on the roads is used. I read thru this litany of problems and some of these same problems were discussed between me and a tech at my local locksmith. My girl just bought this Trailblazer and she likes it but we got no key fobs with it. The shop tried to program two new fobs with no luck. While we talked the tech said he has seen the problems mentioned here with ignition switches and grounds. He also talked about the same thing @TJBaker57 had, about the modules talking with each other and something I already knew, that modules are pretty heavy duty and it is rare of a module to die but can on rare occasions happen. I would have to have a response full of "quotes" here to mention all members here that chimed in with helpful info like @Mooseman and @Reprise did as well. I had already planned to check and address all grounds and inspect every fuse and relay I can get my hands on. Fortunately, here in the PNW, rust is not a problem. When the locksmith tech mentioned the ignition switch possibility and after I read this thread, it seems a new ignition switch is in my future. I am a very proactive mechanic after retiring from that field after 35+ years, yes I say mechanic and not technician, I am old. I am very familiar with how wires can break and get damaged inside the convoluted rubberized protection when they are opened and closed so many times and have seen at least 20 times where wires have rubbed thru insulation of each other when laid across each other and vehicle vibes work on them over the years. Sorry to hijack this thread but I feel like my girl's rig will benefit from what I have learned here. In my case, an old dog can be taught new tricks. By the way, after buying the Trailblazer, @TollKeeper, a member with me at TYF, recommended joining here for insight.
Thanks for the detailed help and I will try to post back with results.
Thanks for the detailed help and I will try to post back with results.
this is going to be long so ignore me if you must but I need a place to let it all out so to speak
After being so proud of myself for what I've accomplished (non electrical) with your insight and on my own through countless hours of YouTube videos and reading manuals, the electrical has me officially defeated. I'm going to be a stereotypical girl right now and cry about it.
I've taken the suggestions here and after doing all I can, my problems seem to be growing. The burning smell is from the fuse box. It is strong behind it at the firewall and I smell it right when getting out and while in the vehicle. I watched Wally take his out on YouTube. I'd be willing to do it but at this point I figure there's some wiring mess somewhere I can't track down and a new block wouldn't solve it. Something is heating it but it's beyond me at this point. What started as that one "lifting" breaker in the rear fuse block is now multiple lifting relays in the front fuse box. Brown/burnt prongs on fuses and relays in the front. No fuses blown. Relays have been swapped to test and replaced just in case after swap-testing fine. They still randomly start coming loose. One day it's 1, 2 hours later it's 2, then next day 3 and an hour later 1. I just keep pushing them back in.
I have more modules that seem to randomly communicate and stop communicating when I'm driving and OBD2 scanner trying to see live data with intermittent loss of communication with various areas for just blips of a second. It will show ECT and then drop connection, come back up and then drop live LTFT or O2 sensor data next. Sometimes it's fairly quickly jumping around and other times all stay good for long time. Never a check engine light thrown (one exception weeks ago for a sensor I replaced and that never came back) yet I have so many drivability issues sometimes, it seems like my dash should be lit up like christmas. So of course, I checked the cluster and the wiring to it. I won't clear codes in scanner and one day it will show history codes and other days it only shows a couple of history codes. Next time only 1. Additionally, the port where I'm plugging in loses power intermittently as well and that's when I'll see everything on the live scanner disconnect and then reconnect. Then it's time to disconnect battery for whatever reason and we start again.
Newer problems are anything from electronic suspension to the electronic break control to four-wheel drive kicking in to radio issues, HVAC issues and more all happening randomly while I'm driving. The scariest is brakes. I'll have brakes at one stop sign but when I need them at another stop sign, they're not there. The other night, I came up to an icy corner slowly like I usually do by my house but this time, it was a little icier than normal and I had no anti-lock brakes. No light on the dash. No code. The next morning, I checked on purpose at that same corner and I had ABS working.
I read and read and read. I follow the diagrams. I see the common wiring to grounds and splice packs so I tackle what I can to no avail. Transmission is beautiful one morning and later terrible. I do understand relearn after reset so I'm referring to independent times outside of that where the transmission is completely unpredictable. I was going to replace the fan clutch but I'm not convinced either are bad because it seems to me the entire vehicle has a mind of its own which could include when that fan decides it is and isn't going to come on and for how long. Thermostat? Sure I may need one. But...do I? Know what I mean? The fan has been the most frustrating because there should be a ground under the left side of the radiator and I don't have anything grounded there and according to diagrams, multiple items ground out at g103 which does not seem to exist for me. Is everything kosher where the fan electrical joins into the corrugated plastic of the main wiring? I don't know. I couldn't reach it to open and check so I stepped away for a break. Lol it honestly makes me feel stupid at this point. Normally that would be motivation to just read more and try harder but today is not that kind of day.
Tonight I raise my white flag. It's better than starting on fire driving down the road.
After being so proud of myself for what I've accomplished (non electrical) with your insight and on my own through countless hours of YouTube videos and reading manuals, the electrical has me officially defeated. I'm going to be a stereotypical girl right now and cry about it.
I've taken the suggestions here and after doing all I can, my problems seem to be growing. The burning smell is from the fuse box. It is strong behind it at the firewall and I smell it right when getting out and while in the vehicle. I watched Wally take his out on YouTube. I'd be willing to do it but at this point I figure there's some wiring mess somewhere I can't track down and a new block wouldn't solve it. Something is heating it but it's beyond me at this point. What started as that one "lifting" breaker in the rear fuse block is now multiple lifting relays in the front fuse box. Brown/burnt prongs on fuses and relays in the front. No fuses blown. Relays have been swapped to test and replaced just in case after swap-testing fine. They still randomly start coming loose. One day it's 1, 2 hours later it's 2, then next day 3 and an hour later 1. I just keep pushing them back in.
I have more modules that seem to randomly communicate and stop communicating when I'm driving and OBD2 scanner trying to see live data with intermittent loss of communication with various areas for just blips of a second. It will show ECT and then drop connection, come back up and then drop live LTFT or O2 sensor data next. Sometimes it's fairly quickly jumping around and other times all stay good for long time. Never a check engine light thrown (one exception weeks ago for a sensor I replaced and that never came back) yet I have so many drivability issues sometimes, it seems like my dash should be lit up like christmas. So of course, I checked the cluster and the wiring to it. I won't clear codes in scanner and one day it will show history codes and other days it only shows a couple of history codes. Next time only 1. Additionally, the port where I'm plugging in loses power intermittently as well and that's when I'll see everything on the live scanner disconnect and then reconnect. Then it's time to disconnect battery for whatever reason and we start again.
Newer problems are anything from electronic suspension to the electronic break control to four-wheel drive kicking in to radio issues, HVAC issues and more all happening randomly while I'm driving. The scariest is brakes. I'll have brakes at one stop sign but when I need them at another stop sign, they're not there. The other night, I came up to an icy corner slowly like I usually do by my house but this time, it was a little icier than normal and I had no anti-lock brakes. No light on the dash. No code. The next morning, I checked on purpose at that same corner and I had ABS working.
I read and read and read. I follow the diagrams. I see the common wiring to grounds and splice packs so I tackle what I can to no avail. Transmission is beautiful one morning and later terrible. I do understand relearn after reset so I'm referring to independent times outside of that where the transmission is completely unpredictable. I was going to replace the fan clutch but I'm not convinced either are bad because it seems to me the entire vehicle has a mind of its own which could include when that fan decides it is and isn't going to come on and for how long. Thermostat? Sure I may need one. But...do I? Know what I mean? The fan has been the most frustrating because there should be a ground under the left side of the radiator and I don't have anything grounded there and according to diagrams, multiple items ground out at g103 which does not seem to exist for me. Is everything kosher where the fan electrical joins into the corrugated plastic of the main wiring? I don't know. I couldn't reach it to open and check so I stepped away for a break. Lol it honestly makes me feel stupid at this point. Normally that would be motivation to just read more and try harder but today is not that kind of day.
Tonight I raise my white flag. It's better than starting on fire driving down the road.
This sucks for you. I/my girl, have the same vehicle and other than my plans to replace the ignition switch, the only problems I have are the speakers. She can live indefinitely without the three speakers working and just listening to one. But I want to make her happy. Sorry to hear about all those problems. Are you saying you are gonna cut bait and get a different vehicle?
I actually changed my ignition switch in hopes that would help some of my initial concerns, but it didn't. In any case, I loved what I learned while doing it. I also have speaker problems. I hope you figure it out for her! I'm kind of a baby and was really disappointed that I didn't have rear speakers working. At this point, yes I am thinking I'm going to junk this out to someone which sucks because when all the pieces fall into place, I cannot believe how incredibly smooth the ride is, smooth the transmission is, how much power is still in the acceleration after 20 years, and overall performance is so so nice and then out of nowhere, I feel like I'm driving a jalopy lol
It was this 2002 with 70k miles on it or a 2006 Toyota Highlander with 185k miles on it with the V6 engine. I used to own a 2002 Tahoe LT. This TB is just a smaller, baser version of that 2002 Tahoe. As I go along I will post here what happens. I have already done a Genuine GM water pump and Genuine GM thermostat with the water outlet housing. I have installed all new Weather Tech mats, front, second row and cargo area. New/used driver's door armrest/pull handle and driver's door check strap. It has the 3.73 gear in it with the G80 rear diff locker. I wish I had that gear instead of the 3.42 I have in my 05 Z71 but I have a BlackBear tune on it and it runs great. Anyway, she wanted this instead of the Highlander and I will get it up to my standards. Anyone who has seen my build thread at the Tahoe/Yukon forum, knows my standards. @TollKeeper is familiar.
Anyway, I wish you better luck and I do have to ask another question, why did you get rid of the Duramax? I used to own an extended cab 4x4 HD2500 with a Duramax and Allison, was an 02. Loved that truck.
Anyway, I wish you better luck and I do have to ask another question, why did you get rid of the Duramax? I used to own an extended cab 4x4 HD2500 with a Duramax and Allison, was an 02. Loved that truck.
She's lucky to have you! My husband is a great man, but an auto mechanic he is not LOL
I did not want to get rid of our truck but it was the oddest situation. We were on a campsite here in Wisconsin. The fuel lines rusted out in a section about 2 ft from the fuel cooler at most and from what I was able to initially see, the cooler was leaking too. I called our regular guy who was very far away but willing to help on the phone and he said to just do rubber lines. He said the thing is so rusty it's not going to live forever, make it work with rubber. I called multiple shops. Absolutely no one would do any type of rubber hose stating they can't guarantee that work so they wanted to do $2600, on average, all new fuel lines etc and I did not want to put that into it until we were sure we could get our issue with the turbo handled first. (Did I mention that truck also had an electrical issue? LOL so did my Buick LeSabre before that? LOL I'm starting to think I really know how to pick them...ha) I decided we would just do it ourselves.
My husband's back had just gone out so he couldn't get underneath to even attempt to try to do it. He had to heal up quickly to leave for work in another state. At that time, I too had some health problems going on and ended up in an ambulance to the hospital so I needed to be taking it easy and not working under a truck LOL..... Here's where it gets ridiculous. After failing to find a shop willing to do rubber, whether it was a patch or rubber from front to back, I had flyers posted in the local auto parts stores, and used word of mouth, with an offer to pay someone $1,000 in labor, plus I would buy the parts obviously, if they would just come to my campsite and do this for me. I also posted a Craigslist ad. I figured by the time I paid that and the parts, I was coming out at around 50% of what it would have cost me at a shop. At this point, we were desperate because my husband had now already left to go to Maine for work and I needed to get out of the campground before the season ended. He had our other vehicle and I had this dead one on the campsite, completely stranded, with no responses for the ad so I finally just had to dump it quickly so I could get off the campsite. Then, I ended up selling the camper because we decided we didn't like this one, and now I didn't have a truck to pull it anyway LOL
--- here's the heartbreaking part. A guy drove all the way from minnesota, a 5 and 1/2 hour drive to me, to lay on the grass, fix those fuel lines in 15 minutes, and drove it away, using it to pull his other truck home on a flat bed. I sold it for far too little but that's what happens when you're between a rock and a hard place on a deadline.
We will be buying another LBZ though. We know what we had with our 06 and how highly sought after that engine is so it was killing us to not be able to get help fixing it. We'll hopefully find one this year sometime. An LBZ is going to cost us a bit more but that's the engine we want.
I am retired from the shops but still like to stay in the field and get dirty. I not only work on my fellow vets rigs from my American Legion and the VFW, I also advertise my experience out as a teaching tech. I charge an hourly rate to show up at a person's place to make sure they do the work themselves the correct way. If they need tools they rent from me. If they have no place they work on it here with my supervision. I also do a mobile and on site service, that I charge for, to do pre purchase inspections of used vehicles and depending on how in depth they want me to go, I charge accordingly. It keeps me busy at times and the rest of the time I travel with my girl and work on our rigs. I am tired of being retired.
Mooseman
Moderator
Like I mentioned in the other threads, it is a shame that this truck is such a basket case that was previously either poorly maintained or repaired by a pair of unskilled or unmotivated hands. I've had my share of basket cases but electrical issues can be some of the worse and daunting.
Maybe a fuse block is something to consider:
http://www.chevroletproblems.com/fuse-block-stall/
I don't fall into a stalling issue or starting issue but I do fall into the intermittent electrical category.
I can't seem to find any information on how tight is tight when it comes to the Jack screws or Jack bolts whatever they are called inside the fuse block. I have them hand tight and I probably could crank them tighter but don't want to bust anything.
http://www.chevroletproblems.com/fuse-block-stall/
I don't fall into a stalling issue or starting issue but I do fall into the intermittent electrical category.
I can't seem to find any information on how tight is tight when it comes to the Jack screws or Jack bolts whatever they are called inside the fuse block. I have them hand tight and I probably could crank them tighter but don't want to bust anything.
- Jul 22, 2015
- 2,724
The thought just occurred to me, so I figured I'd logon and see if anyone can confirm from memory...
Does the underhood fuse block on the 360 series have 'wire tracers' connecting everything together on the underside, like the full-size trucks do? I know the ones on the FS 99-06 (800s) are known to have those wires degrade / corrode / break / etc.
If they're similar, it would be worth checking out. I know the underhood box isn't terribly difficult to remove from the FS trucks (of course, there's more room everywhere, too).
It would be a bit of a relief to find out that the issues OP is having could be traced back to a common / central source.
OP -- hang tight until someone confirms (or I find the info, which won't be until tmrw). Thx.
Does the underhood fuse block on the 360 series have 'wire tracers' connecting everything together on the underside, like the full-size trucks do? I know the ones on the FS 99-06 (800s) are known to have those wires degrade / corrode / break / etc.
If they're similar, it would be worth checking out. I know the underhood box isn't terribly difficult to remove from the FS trucks (of course, there's more room everywhere, too).
It would be a bit of a relief to find out that the issues OP is having could be traced back to a common / central source.
OP -- hang tight until someone confirms (or I find the info, which won't be until tmrw). Thx.
I'll hang tight. I took the fuse box apart today as far as removing the top with the clips, inspected everywhere a fuse would slide in and grab and saw no evidence of any damage. I didn't even see a hint of discoloration from overheating actually. I opened each plastic square underneath after freeing them from the bolts and cleaned some dust and a dead bug out LOL I looked at all wiring going in on those 3 outer edge connectors (two on one end, one on the other) which also grabbed firmly. I know Wayne's video on YouTube showed an additional layer that had all the copper wire routing that can require welding (which is what I think you are asking others about in your post) but I did not go further than taking my top layer off and taking out the boxes underneath and inspecting. To be honest, I eventually had so much torn apart in there as the day went on, following wires, cleaning connectors, and double checking everything at the PCM too that I got nervous about going much further lol. I was relieved that it even started again haha.
Side note.. saw a post online from a guy who said he would not blow fuses but relays would come loose which is exactly what's happening to me. He resolved it by putting a layer of foam beneath the plastic boxes in the bottom tray, I apologize for my ignorance not having the terminology correct, but basically what he did is force those boxes to stay gripped up on the pins and he never had his relays come loose again. When I unscrewed my bolts and undid the clips to lift the top of the fuse box off, I noticed that the white box fell loose and the gray one next to it was barely on. Yet the center one and the box closest to the windshield were on quite tight by comparison. I had to continue messing with those bolts to release them yet the two closest to the front end were loosey goosey. Upon putting things back together, bolts are all tight but relays are still lifting after a short drive. It seems to happen within minutes.
Adding a link to a video of me getting started. It shows the boxes I'm referring to and I did open them and look at each wire. Pretty as a picture and seem firmly in place. Hopefully that will help my crappy terminology match up to my explanation. I sound defeated already and I was just getting started lol
Mooseman
Moderator
Yep, our fuse boxes have those copper traces. This video shows how to completely take it apart to get to those traces.
This thread shows a fuse box that had a broken wire trace that was soldered back together.
gmtnation.com
And this post shows another one that had a broken trace that was repaired using doorbell or house thermostat wires. I would prefer this method over soldering as the solder could melt if it got hot.
gmtnation.com
This thread shows a fuse box that had a broken wire trace that was soldered back together.
P1682, P0689, P2176 codes and no start when warm
Well, the fuse block bug bit me this week. Drive to work Monday, Tuesday, and Wednesday mornings, temps in the 20s, drive home for lunch, temps in the 40s. Truck won't start to drive back to work. Cranks over strong, spins fast, no combustion. Fired right up when I got home from work, temps...
gmtnation.com
And this post shows another one that had a broken trace that was repaired using doorbell or house thermostat wires. I would prefer this method over soldering as the solder could melt if it got hot.
P1682, P0689, P2176 codes and no start when warm
Well, the fuse block bug bit me this week. Drive to work Monday, Tuesday, and Wednesday mornings, temps in the 20s, drive home for lunch, temps in the 40s. Truck won't start to drive back to work. Cranks over strong, spins fast, no combustion. Fired right up when I got home from work, temps...
gmtnation.com
I took apart the fuse box and all copper looks great. Bolts are back in and I was super diligent about making sure I had no metal from having to file off the bolts when replacing them. I've been through the entire front end wiring and I'm moving into the dash and inside electrical components now. This will include double checking my data bus lines etc. Knowing my burning smell is behind the fuse box, I dug into those wires that go up to the ground points and I see what appears to be a lot of electrical tape from some previous work. The corrugated plastic is pretty loose and open as well so I'm able to take a look and all of my colored wires look great so I'm looking at moving where they go through the rubber boots into the body. However, I noticed a piece of rubber or plastic, flat and rectangle, sticking out of the corrugated plastic and about 12 in up, another end of it sticks out. I opened the plastic casing to look at the wires again and this seems to be adhered to the back of the braided ground strap through a chunk of the harness but then separates from it and sticks through the corrugated plastic in two spots. Close examination shows what looks like could be embedded metal inside this flat black rubber. The closest I can find on Google would be something static related. Can someone shed light on what that is and where I may find end points for replacement if needed?
Mooseman
Moderator
editing this to add a fourth picture from a distance to show what I'm talking about with the up-close photos. Sorry. I thought of that right after posting and was going to edit to add them and completely got sidetracked. Here you go. It's not really attached to the ground strap but what I'm trying to explain is that it seems to run parallel right up but it against it but can't be serving a function if it's not connected to anything. At first glance, it appeared to be attached to me but I see the electrical tape is what's holding it up tight against it. Picture two is where there is a split in the Y to the hood and then the ground bolt.
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An intrepid Artillery Gunnery Sergeant once made the comment:
"If you Keep Missing The Mark... MOVE YOUR SIGHTS... BOLDLY..."
You might take a Leaf out of his Book by visiting THIS Link at eBay:
...and browse through all of the Used , COMPLETE (All Three Sub-Components) Under Hood Fuse Boxes of the 2002-2005 Vintage. Try to find a Clean, NON-Desert Area, inexpensive version that you can simply PLUG-N-PLAY as a fairly straightforward way to eliminate any existing, hidden issues with Cracked Copper Traces that would take forever to probe for continuity, etc.
If you decide to do the same thing with your BCM Under-Seat Unit... you just have to swap in your original BCM Sub-Module that is VIN Keyed to your SUV.
NOTE: Unexplained or Repeat Electrical Failures is a BIG RED FLAG that should prompt doing what follows:
You should get a very bright flashlight and go over all of the Wiring Bundles, Sheathing and Connectors looking for signs of any Rodent Infestation represented with the artifacts of North American Deer Mice building nests, urinating and defecating and also signs of their chewing and gnawing on Wire Harnessing, Plastic Connectors and gathering Pine Needles, Fur and Hood Insulation for their Vermin Home Building efforts. A favorite spot is located under the Fuse Box Mounting area adjacent the Battery Box.
Use GREAT CAUTION if you see any of the signs of their presence mentioned above. Deer Mice harbor the Dreaded HANTA Hemorrhagic Fever Virus that kills nearly 40% of the people who inhale or transfer the desiccated Dusty Urine & Feces into their mucous mouth linings and lungs. So wear a Quality N-95 Mask AND use 11 Mil Nitride Gloves to protect your hands while removing their detritus, repairing wiring with Solder and Heat Shrink and while cleaning up after these awful little beasts.
If you discover this to be the problem and manage to sort things out ... use THIS Product to discourage their unwelcome return:
"If you Keep Missing The Mark... MOVE YOUR SIGHTS... BOLDLY..."
You might take a Leaf out of his Book by visiting THIS Link at eBay:
2002 trailblazer fuse box for sale | eBay
Get the best deals for 2002 trailblazer fuse box at eBay.com. We have a great online selection at the lowest prices with Fast & Free shipping on many items!
www.ebay.com
...and browse through all of the Used , COMPLETE (All Three Sub-Components) Under Hood Fuse Boxes of the 2002-2005 Vintage. Try to find a Clean, NON-Desert Area, inexpensive version that you can simply PLUG-N-PLAY as a fairly straightforward way to eliminate any existing, hidden issues with Cracked Copper Traces that would take forever to probe for continuity, etc.
If you decide to do the same thing with your BCM Under-Seat Unit... you just have to swap in your original BCM Sub-Module that is VIN Keyed to your SUV.
NOTE: Unexplained or Repeat Electrical Failures is a BIG RED FLAG that should prompt doing what follows:
You should get a very bright flashlight and go over all of the Wiring Bundles, Sheathing and Connectors looking for signs of any Rodent Infestation represented with the artifacts of North American Deer Mice building nests, urinating and defecating and also signs of their chewing and gnawing on Wire Harnessing, Plastic Connectors and gathering Pine Needles, Fur and Hood Insulation for their Vermin Home Building efforts. A favorite spot is located under the Fuse Box Mounting area adjacent the Battery Box.
Use GREAT CAUTION if you see any of the signs of their presence mentioned above. Deer Mice harbor the Dreaded HANTA Hemorrhagic Fever Virus that kills nearly 40% of the people who inhale or transfer the desiccated Dusty Urine & Feces into their mucous mouth linings and lungs. So wear a Quality N-95 Mask AND use 11 Mil Nitride Gloves to protect your hands while removing their detritus, repairing wiring with Solder and Heat Shrink and while cleaning up after these awful little beasts.
If you discover this to be the problem and manage to sort things out ... use THIS Product to discourage their unwelcome return:
Random guy in parking lot saw me sniffing my engine LOL I said oh just doing the usual sniff test and trying to see if this rubber plastic thing is important and he said oh I think that's a stiffener don't worry about it. Sooooo ok maybe I'm alright there.
Mooseman
Moderator
That wire loom to the hood is inconsequential to anything you're chasing down. There's just a ground wire for the hood itself and the wires to the underhood light, which usually doesn't work because the bulb is burnt, the switch doesn't work, wires are corroded or the bulb was removed to prevent it from draining the battery because the switch is often defective and keeps the light on all the time.
I think they ground the hood for electrical noise suppression.
Since the fuse box's copper wires seems to be good, next thing to do would be a pin drag test on all the sockets before you spend any kind of money on another one. Did you check BOTH sides of the fuse box traces? As per this video, it's apparently the top side that usually has the issues.
And you could do the pin drag test while that top side is exposed. Just insert one leg of a fuse or relay at a time see if you feel some good resistance pulling it back out.
I think they ground the hood for electrical noise suppression.
Since the fuse box's copper wires seems to be good, next thing to do would be a pin drag test on all the sockets before you spend any kind of money on another one. Did you check BOTH sides of the fuse box traces? As per this video, it's apparently the top side that usually has the issues.
And you could do the pin drag test while that top side is exposed. Just insert one leg of a fuse or relay at a time see if you feel some good resistance pulling it back out.
In either this thread or my one about the circuit breaker leg popping up, I remember people saying their fuse box did not look like mine. I had been checking fuses by comparing to the diagram. However, when I opened my manual from the glove box, I see a different configuration as well as a blank spot for where that 15 amp circuit breaker is. Is it possible I don't have the right rear fuse box and how much would that matter for my potential odd wiring problems? Since posting about the lifting circuit breaker leg, I have removed that breaker. Additionally, I don't have a relay in for the RR fog LP because I was told I wouldn't have to worry about it right now. Let me know your thoughts on why my fuse box would have a lid with fuse information that does not match my manual in the glove box. The lid actually doesn't seem to match either one actually. It does not even have the relay in my fuse box that I circled listed at all. I'm assuming I would want to follow the layout in my manual regardless of what the box and lid look like?
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Mooseman
Moderator
We don't have RR fog lamps in North America. That's an export option. The same fuse box is used for many different configurations so it's normal if there are empty or undocumented slots. It's the same for the underhood box. If you don't have fog lights or headlight washers, those slots for the fuses and relays would be empty and usually won't even have the connectors inside them.
Okay so that makes sense with I think what someone, maybe you, had explained before and I had forgotten. I guess I'm wondering if it's possible I have fuses plugged into spots that may have power but aren't run through a full circuit necessarily. For example I have fuses in the block for a sunroof, and that is in my manual, but my vehicle does not have a sunroof. I suppose it's possible that under the top layer there's not actually any power connected there, but without looking, if there was, would that potentially cause electrical issues since I don't have a full sunroof circuit? Hopefully that makes sense what I'm trying to determine.
Editing to add that I realize the fuse does not necessarily supply the power and it's only part of the circuit but what I find interesting from the wiring diagrams is that there is a direct battery line as far as I could tell and in my mind that just feels wrong that there's a hot at all times connection. Maybe it really doesn't matter.
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