Electrical help needed

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Thanks Khalid, I appreciate your kind words again. You just play the cards that were dealt to you. There’s really not much you can do. Ok, back to my TB. I’ve read that there is a park lock solenoid by the shifter. Would this cause my key to not turn back and be removed ? Is there any special way to remove the console in my 2003 to access it ? How does the shifter handle come off ? I was wondering if any springs were gonna come flying out once the handle is removed that are connected to the button on the shift handle or if it just slides off. I did do a search here but couldn’t find anything. Many thanks in advance.
 
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Mooseman

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Dec 4, 2011
25,358
Ottawa, ON
The handle comes off easy. There is a small Torx set screw at the front of the handle holding it in, and you just pull it off. The console is a different story. Lots of hidden screws under the rubbers for the cup holders and inside the armrest storage. Wiring also for the rear fan. The shifter stays in place.

The interlock on the shifter is the one that keeps the shifter locked until you press on the brake. Away from home right now so I can't remember where the shifter position sensor is located (on the shifter or the tranny). I believe if the BCM thinks it's not in Park, it won't allow the key to be removed (or the battery is dead but that's another story). On that thought, it is possible that the solenoid key unlock is dead or not getting the power for some reason. If you had a good scanner like a Bluetooth adapter and Torque app, it could tell you if it senses the shifter in Park or not.
 
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Mektek

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May 2, 2017
656
FL
I had both problems. PO spilled coffee into the console and that sticky liquid eventually caused the shift lock solenoid to stick and unable to shift out of park. Really sucks when it happens late at night far away from home. :mad: pulling apart the console with pliers and a flat screwdriver under flashlight is not fun.
Stuck lock cylinder happened last month. Only after wiggling and rotating a few times it finally allowed full rotation to remove the key. Fortunately the fix was simpler - spray into and around the lock cylinder with wd40. Rotate the cylinder a few times and pull the key and insert it (if you can) to distribute the oil. Since I did that last month the problem has not returned.:thumbsup:
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Thanks Mooseman for the reply. I went out to start it this morning and got the usual just click when I turn the key to start. It did however turn over on the fourth try instead of ten minutes of trying. I went to pop the hood to install the new starter relay but there was so much ice on the hood I couldn’t open it LOL ! I brushed off the snow and hopefully the sun might melt the ice enough to get the hood open. I have a feeling I did something in the shifter the other day when I slammed it in low when I was trying to get it to turn over thinking a switch may be stuck. Ok, if anybody can confirm that the park/interlock solenoid is on the shifter assembly on my 2003 TB ? If it’s not functioning as it should, would it cause the key to not turn back and be removed ? Thanks again

Thanks Mektek for the tip. Unfortunately my problem is a little different. My shifter will come out of park and the TB will start. It just comes out of park now without pressing on the brake and the key can’t be turned back to be removed. Thank you for your reply.
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Just an update. My TB has a new AC Delco ignition switch same problem with not turning over. I also replaced the starter relay and have same problem. Crazy thing is that it’s been unusually warm here in Buffalo NY and it turns over and starts right up. I’m guessing there is something wrong with the park solenoid by the shifter because my key still won’t come out unless I press the button by the key cylinder. Any other ideas I’d love to hear them. I should be messing around with it this weekend. Many thanks in advance.
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Hello again. I could really use some expert help. I’m pretty much at my wits end with this TB. It started up just fine and I backed up out of the driveway. When I put it in drive from reverse it stalled and will not not crank. It’s actually in the middle of the street as I type this. I’ve been waiting on a tow truck to shove it back in the yard for 3 hours. While I was sitting there I tried jumping the starter relay. It will turn over but not run. The key will still not come out and it won’t crank in either park or neutral. One thing I did notice is that the indicator below the PRDLL is no longer showing up on the dash and the check gauges light is on but I’m guessing that’s because the gas gauge goes to empty for some reason. I do hear the solenoid by the shifter clicking when I turn the key. Any ideas guys ? This is my only vehicle and I’m basically stuck without it. Please help if you can before I lose my mind.
 

mrrsm

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Post Message #3

https://gmtnation.com/forums/threads/02-trailblazer-transmission-replacement-issues-solved.17907/

This Video will show you where the Park Neutral Switch is located on your GM 4L60E Transmission and How to Adjust The PNS position properly to allow the other Safety Harness interactions with the PCM to allow the vehicle to safely start when NOT In Gear and be able to insert and extract the Ignition Key when it is actually safe enough to do so:


You should pay particular attention to what the VOP says about "The Pink Wire" and the problem of losing Dashboard and PRNDL Lights in this video:


There is one other very important thing to remember... You can indeed have the Finest OEM AC-Delco Ignition Switch ever made... but if during the installation... that "Rack and Pinion" Row of Gear Teeth are moved out of place by even ONE TOOTH... It will NOT function properly. If you still have your Old Switch... Examine it Very Carefully and then cycle it through its motions back and forth and try to reason out how the Ignition Key Block Rotates it from one position to another and then observe your latest one after removing it and compare what its position is once you take it out ...without changing anything ...and then re-examine those Rack and Pinion Settings to ensure that it gets Selected and Installed correctly when you put that switch back up into the Steering Column.
 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Thank you very much for the reply MRRSM. I will take a look at the videos. I have a suspicion of whatever makes that indicator light show up under the PRNSL on the dash is the culprit. It was just strange that as soon as I put it in drive after I was backing out of the driveway it stopped running and would not turn over ever since. A bunch of neighbors came out and pushed it into the yard for me so at least it’s no longer in the street lol. I did swap the ignition switches just to see but same results. I put the new one back in. I’ll have to look for a video for the ignition install to double check I did it right but I’m confident I did. I did not unhook the negative battery cable though. Thanks again
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Ok just an update but unfortunately not a good one. Same results. I did doublecheck the ignition switch again and swapped out the old one. I believe I have it lined up correctly with the second large gap out of view and the first small tooth still in view. One thing I did observe is the steering wheel does not lock with the key out. After I press the button under the key cylinder to remove it, I can turn the steering wheel left and right and it does not lock. Does this symptom add to what might be my no crank problem ? Many thanks in advance.
 

Reprise

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Hijacking this thread for just a moment...

You should pay particular attention to what the VOP says about "The Pink Wire" and the problem of losing Dashboard and PRNDL Lights in this video:

The other thing that was mentioned toward the end of the video - the TB had a bunch of transmission codes - and the guy on the video mentioned that that was because of the pink wire, as well (b/c the trans gets power on its sensors from...the pink wire).

Documenting that here, in hopes it shows up in search for the next person looking for why they suddenly have several different fault codes triggered for the transmission.

(and for what it's worth... I like the 'South Main Auto' YT videos, of which this was one)
 

mrrsm

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There are several complex Electrical Players involved here also that marry up with PHYSICAL, MECHANICAL COMPONENTS that make all of this into quite a Nightmare. Adding to this difficulty is the condition of your Truck Battery. When the Engine is Turned Off... if the Battery is marginal or without a Good, Saturated Charge... if the Engine Dies at Idle and in gear... even if you manage to move the Shift Lever into the Park or Neutral Position... without sufficient Energy available the Park Neutral Solenoid and The Shift Lock Solenoid may not respond and signal the PCM to be aware that the Truck is indeed Parked and At Rest. So you should probably ad that to your list of things to investigate and Testing the Battery when Under A Load is the only way to discover any problems with Excessively Oxided Lead Plates or any Dead Cells. So taking it out of the truck and over to Autozone will be a good idea to eliminate any guesswork about this. There is a correct cascade of proper events that you need to understand must occur before your Truck will Start and Run (...other Members may jump in here at any time and make corrections to this List if any errors or omissions are noted)... Here We Go:

(1) The Driver places the Ignition Key into the Steering Column Key-Lock and slowly rotates the Key Clockwise until ... IT STOPS DEAD
(2) He realizes that First... He MUST Step on the Brake Pedal to disengage the Shift Lever Solenoid and move the Shift Lever from the Park Position.
(3) When he rotates the Key to Run, the Ignition Switch Circuit actuates the Accesories Circuit and Fuel Pump Relay to close, Priming the Fuel Pump.
(4) When the Driver Rotates the Key to the START Position... The Ignition Switch makes the contacts inside to close the Starter Solenoid Circuit.
(5) The PCM uses the Inputs from the ACC Pedal, The TPS, CKP and MAF Sensors sending discreet signals all COP Spark Plugs to Fire Sequentially.
(5) And as the Engine starts,,, The PCM is waiting for the O2 Sensors to warm up enough to give correct readings to adjust the Fuel Flow vs O2 Levels.
(6) If the PCM reads the Inputs at idle from the ACC Pedal, TPS, CKP, CPAS, CPS, MAF and O2 Sensors... The Engine should Idle nicely at 600 RPM.
(7) When shifted into gear... the ACC Pedal signal opens the Throttle Body and the additional incoming O2 prompts the O2 Sensors to ADD More Fuel.
(8) The PCM reads all of the sensors and depending upon various RPM ranges, uses its tables to make Long and Short Term Fuel Trim Adjustments.
(9) Assuming the Fuel Tank is sufficiently full... The Engine will run until the Fuel Runs Out, Something Breaks... or the Ignition Key is Turned Off In Park.
(10) If ANY or ALL of the PCM System Sensors AND THEIR WIRING suffers a failure... The Engine will suffer in greater or lesser degrees to perform.
 

Adjustso3

Original poster
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Dec 10, 2017
112
Buffalo, NewYork
Once again, thank you MRRSM. As soon as I have an opportunity tomorrow, I will get a ride to AutoZone and have my battery checked out. I have never been a fan of the Everstart batteries which is what is in my TB right now. I may just replace the battery with a Duralast brand. What I’m very confused about is that little “indicator” light that is usually under the PRDSL gear display. It is NOT there anymore. Why would this disappear ? Another question. Should I assume the park/shift solenoid is good because I can hear it clicking ? Is the silver button on the Park/shift solenoid used to manually put the shifter into neutral if the shifter is stuck in Park ? The reason I’m asking is because the transmission can be shifted out of park now without pressing on the brake first. I’m just wondering if everything is pointing to a bad Park/shift solenoid because the truck won’t start, the key won’t turn back and be removed, and the shifter moves out of park without depressing the brake pedal ? It’s freezing out and we have about a foot of snow so it’s kinda tough to work on it along with having a messed up back, so I apologize for trying to pick everyones brain. Would it be ok to manually trigger the ignition switch without installing it to eliminate the possibility of a tooth or so off ? Would the TB run without it installed and just plugged into the connector ? Many thanks in advance and will continue to troubleshoot in the morning.
 

mrrsm

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My Old EOD and TAC team Instructor used the expression,,"You Can't Get THERE... From HERE..." ...and neither can you... First Things First. I wrote up that List to suggest that you do likewise... Or else making your Automotive Diagnoses OUT OF ORDER is bit like Trying to Take Your Pants Off... Over Your Head... :>) Start with the Question "Do I have A Good Battery...?" and proceed by taking things in Orders Of Operation...working through one item at a time. Any good Scientist will tell you..."Only Change or Examine One Variable at a time..." and then see how it affects the entire system. Even the instructions for dealing with Trouble Codes ("P" Codes) will advise you to "Take Each Code In the ORDER of their Listing..." Forget about trying to eat this Elephant with One Big Bite... and THINK carefully about WHY certain things are coming up in the scheme of this problem. Think about it this way... "All of these malfunctions begin and end with ELECTRiCITY..." Either its Flow or re-direction in timely ways using Discreet Switches and Sensors to perform unique jobs at special times and in their proper order. Yet, each one requires the Proper Electrical Voltage and Amperage to perform correctly.

Get a New Battery.... Then Chock your Wheels ...and after installing it... Put the Key in the Ignition and Turn It to Run and STOP to investigate whether or not you can place the Shifter correctly into the Park Position. Then turn the Ignition Off and Rotate the Steering Wheel to see if the Steering Wheel Lock Engages... and so forth and so on... One Thing At A Time... Then observe the Dash Panel for the Presence of the PRNDL Light...and remember what the VOP said about "The PRNDL Light did NOT come on because of a Problem with the Ignition Switch ...and "The Pink Wire" issue.... as soon as the Ignition Switch was replaced and the a "P" Codes were cleared... No More Problems.

If you manage to get the truck running... Take it right back to the place where you purchased your New Battery and ask them to Test your Alternator for any Problems... as ALL Batteries require OVER 12 Volts of Charging Power in order to be Refreshed with New Power so it works during the running of the vehicle well enough to keep the New Battery from Running Down and starting this Electrical Failure Cycle all over again. A Bad Alternator will RUIN a Good Battery Down FAST and an Inoperative Alternator will cause the Engine to RUN ON BATTERY POWER AND SCAVENGE POWER FROM THE DASH LIGHTS AND UNNECESSARY ACCESSORIES IN ORDER TO KEEP THE ENGINE RUNNING UNTIL IT QUITS FOR LACK OF GETTING NEW JUICE! So... if you have not been seeing the PRNDL Light and Dash Lights glowing brightly... THIS might be the answer as to WHY...
 

christo829

Member
Dec 7, 2011
502
Fairfax, Virginia
I'm not going to be able to add to what you've already been told, but just chiming in to say that our trucks do not
have locking steering wheels, so you don't need to worry about that as a possible symptom/issue.

Good Luck!

Chris
 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Hello MRRSM and christo829. Thanks for the reply. I will be going to purchase a new battery in a couple hours. I didn’t know about the wheel not having a loch mech. Thanks for the info, I didn’t know that about our trucks. As soon as I replace the battery I’ll report back about my findings. Thanks again for the help.
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Hello again. I said I would report back. I purchased a new battery from AutoZone and it’s installed. Turned the key and no crank just like before both in park and neutral. I swapped the new ignition switch with the old and have the same results. I put the new switch back in and adjusted the teeth from a video I saw. It said to leave the connector on and adjust the switch until all dash lights go off including the battery light which will be the last to go off. I’m now stumped and had to come inside because it’s freezing outside. There is no click when I turn the key forward and the key will still not come out unless I press the button. Shifter still moves out of park without stepping on the brake. Any other suggestions ? Many thanks in advance.
 

mrrsm

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It will be helpful if you would Post the Links to any sites that offer help that is useful to you back here and also any Links to Videos you have watched ...so we can look at what you have been viewing as well to compare ideas here.

This is a Quote from another Site:

http://www.greatautohelp.com/forums/viewtopic.php?t=5333


05-07-30-021, 05-07-30-021a, 05-07-30-021b are TSB's that have to do with the key not being able to come out of the ignition switch. The shifter boot may be caught in the shifter assembly mechanism. Happens on trailblazers from 2003 t0 2008. “

“check your BTSI fuse #25 in the underhood fuse box for power and for connection. it powers up the shiftlock solenoid.”
 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Thank you for the reply. The shift boot is actually off right now so that isn’t the problem. I can also hear the solenoid clicking when I turn the key so I would assume it has power. Is there a part that’s function will not allow the key to be turned back and lets the shifter move out of park without stepping on the brake pedal ? Would this be the PARK/SHIFT SOLENOID ? Even though I can hear it clicking, can it still be bad ?
 

mrrsm

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I'll answer your question with a Dangerous Hypothetical Story:

Mr. and Mrs, Smith and their 5 year Old Son..."Little Smitty" are about to take a Road Trip ...and while "The Men" are waiting for Mrs. Smith to finish up doing her Hair in the Ladies... Mr. Smith loses patience and dashes into the house to roust the Lil Woman so they can all get on the Road. Meanwhile... "Little Smitty" has been eye-balling the Old Man's Key Fob that he left dangling in the Ignition Switch and the Kid reaches over to fiddle around with it...and Well... What do you think would happen if "Little Smitty" accidentally started the SUV...and then remembered that his Dad made the Truck GO by squeezing the Handle next to his seat and Whooosh... You Get The Idea? That BRAKE PEDAL requirement is a Poor Man's Substitute Baby Sitter to avoid what is suggested in their story. :>) So Yeah... YOU need to Step on the Brake to Start the Vehicle...

And the OTHER Safety Gizmo at Play here is The Park Neutral Switch... If "Little Smitty" was able to accidentally Start The Vehicle while IN GEAR.... Well again... You get the Idea... So if your PNS has Gone South or is as "maladjusted" as "Little Smitty" is... Or if The Dual Harness Wires to the PNS have been CUT ...or if its two Plugs have been Damaged and the PNS cannot signal the PCM that there is a Human Being in control of the vehicle under SAFE conditions (Either actually IN Park or actually IN Neutral) .. then The Truck Simply Will Not Start.
 
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Adjustso3

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Dec 10, 2017
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That’s a good example in story form. I agree I need those to work. Ok, it sounds like there are two parts that could be giving me my problem instead of just one. Any idea if either are causing the indicator to disappear in the PRDSL display ? There used to be a curser under the P if it was in Park and the D while in drive etc. As soon as I had this problem the indicator is now gone. I’m just guessing the missing indicator may point to the root cause of my problem. So you’re thinking it’s the Park neutral switch ? Are you talking about the neutral safety switch on the tranny or the shift lock solenoid on the shifter ? Sorry, I guess I’m a little confused. This particular problem started when I was backing out of my driveway. When I was in the street, I put it in drive and it stalled and has been like this. Thanks again, I appreciate your time.
 

mrrsm

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I know that you are sick and tired of hearing this.... But I still cannot shake the idea that there is STILL something very FUBARed between the New Ignition Switch and the Key Lock Assembly. Have a look at this excerpt and compare it EXACTLY to what you did and determine if you made any mistakes when installing the Ignition Switch.... Skip all of what you've tried already with it and start with a Clean Slate to analyze these steps versus your own... and if you find ANY discrepancies... Then opening up the TOP of the Steering housing to access the Key-Lock Mechanism and PASSLOCK Harness might be necessary to solving the problem. I know that it is Colder than a Klondike Well Digger out there...so perhaps you can plan to look things over when Daylight comes and you can get rested for your next attack. There are more videos available on Youtube to show how to access the Upper Steering Column to get up close and personal with the PASSLOCK Wiring. and Lock Work..etc.

Focus on this LIST...but later...READ THE ENTIRE POST AT THIS LINK... There is a Surprise Discovery in the Dialogue that Might Help You:

http://forums.trailvoy.com/archive/index.php/t-29322.html

Important: The gears between the ignition switch and the lock cylinder housing must be in the correct position. Failure to do so will cause a misalignment of the gears in the ignition switch and the lock cylinder housing, which may result in a NO START or BATTERY DRAIN.
1. Verify the alignment of the gear (1) in the ignition switch (2). If gear (1) not in position shown, turn gear in ignition switch (2) until you reach the correct position.
2. Use a screwdriver to rotate the lock cylinder housing gear counterclockwise until it hits a stop.
3. Connect the connector to the ignition switch.
4. Insert the ignition switch into the lock cylinder housing. The tabs (2) on the ignition switch MUST be seated inside the lock cylinder housing (1) for proper installation.
5. Use a screwdriver to rotate the lock cylinder housing gear clockwise to the START position - allowing it to spring return into the RUN position.
6. Align the lock cylinder and install the lock cylinder into the lock cylinder housing.
7. Connect the passlock and key buzzer into the lock housing.
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Thank you MRRSM. I will definitely be giving that a shot in the afternoon when it’s a bit warmer out. I was thinking the same thing about the ignition switch that’s why I even put the old one back in. I’ll try your method in the afternoon and report back. Thanks for helping me MRRSM and sticking with this problem. It’s really driving me crazy. On a side note, the “original “ symptoms with the old ignition switch before the no start and shifter movement without touching the brake were that in the morning I would have to turn the key 25-30 times before it would partially power the starter, then the following key turn it would crank and fire right up. That’s when I replaced the ignition switch and then the following day the starter relay. Just to give you a time line. 3 days all were good and then the back out of driveway/stall/no crank. Thanks again. I really appreciate it.
 

mrrsm

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No Problem, Brother ...Happy to Help...and Always Hopeful that We can Figure Things Out ...at GMT Nation!

Before You Start Doing Anything…. DISCONNECT The Battery Negative Ground Cable. (8MM). Okay…. This is a video that might be called a Perfect Instructional for the R&R of the GM Trailblazer and GMC Envoy Ignition Switch and it gives you the opportunity to re-examine what you did on the two occasions when you R&Rd the Ignition Switches into and out of your Vehicle. However…. THIS TIME...It only serves our purposes in demonstrating How To Completely Remove the Plastic Steering Column Shroud-Clam Shell and exposing what we are REALLY are interested in accessing:

The Upper Cast Metal Steering Lock-Work Housing and Key Lock Cylinder:


Take a look at THIS video strictly for the purpose of observing How To Extract The Key-Lock Cylinder and exposing the internal Lock-Work Housing Hollow Tube that holds it in place. Ignore the fact that this vehicle is NOT in the same year Make and Model as yours… we merely need to observe the techniques involved during this Removal Phase and observe How The Electrical Wiring Harnesses and Connectors Are Being Removed… VERY CLOSELY:


Same Thing Here…. Observe EVERYTHING for Variations on How This Job Gets Done:


If you watch this video a few times… you will notice an Electrical Connector Harness on the Top of the Column…. This Wire Harness leads to the PASSLOCK Internal Device that allows the Final Ignition Circuitry to Connect to the PCM and Electronics that control Starting and Running the Vehicle … Once the Right Key is Inserted and Turned. If you can Jiggle this Harness & Connector, THIS might be right where the problem is located.

THAT harness connection needs to be pulled free and inspected inside and out… searching for any Loose or Broken Wires. Take special note of how easy or hard it was to pull the plug free from its insert point. You are looking for anything resembling extreme looseness that would allow engine vibrations to break the ignition circuit and disturb the PASSLOCK enough to cause it to react as though the vehicle was being STOLEN.

Next … Examine the Key Lock Cylinder Body exterior for signs of Cracks or Wear and any excessive internal Key Looseness when inserted and turned and observe any sounds of rattling or parts shaking loose inside when vigorously shaken back and forth. Remove the Key from the Cylinder and Examine the Key Way for signs if extreme damage such as that which a screwdriver would cause if inserted and used to try and turn the Key Cylinder without the Key. If the Entire Key-Lock Cylinder is Very Loose inside of the Steering Column… it may not allow the Key-Lock Cylinder Gear Teeth to Properly Mesh with those of the Ignition Switch Teeth. These are Cast Metal Parts making up the Steering Column Hardware and there may be obvious fractures or damage inside the tube portion of the Steering Column hardware.

THIS Video will show you just how Ugly this Job can get if you have to disassemble the Upper Steering Column Cast Metal Housing and allow access to the “GUTS” inside: (But you can do this same repair WITHOUT having to remove the Steering Wheel and any other Paraphernalia). THIS Video is VERY Important for you to WATCH!:

 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Hello and thanks for the videos. I was unable to work on the TB today. I have a messed up back and basically can’t get out of bed today. Hopefully tomorrow I’ll be able to work on it. I’ll report back as soon as I can. Thanks again
 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Good morning MRRSM. I re read your post and watched the videos you posted again. A lightbulb did go off in my head. I’m not sure if you have read my entire thread but I would like to point a couple things out. The one thread you posted talked about one guy being able to open the rear hatch and then everything worked and the TB was able to start. My first couple posts asked why my power seats, seat heaters, rear wiper, and keyless entry wouldn’t work. I can’t remember but maybe the interior lights wouldn’t go out either. I started pulling and checking fuses under the back seat and all of a sudden the interior lights came on and then dimmed. I crawled out of the back seat and tried my power seat and now everything worked including the remote locks ! This lasted a few days and then stopped working again. I have checked the rear hatch wires and all looks good. I was suspecting the LGM but was going to leave that repair until warmer weather. Is there a possibility of all of this being my LGM ? I was in a pinch for a four wheel drive vehicle and was sold a mess from a private seller. Everything worked good for a couple days but it’s been a nightmare ever since. I just wanted to bring this up and maybe an idea would pop into somebody’s head. Other than sending it to the dealer which there’s no way I can afford or as a last result, sending it to the junkyard. One thing I’m sure we all can agree to is this TB is an electrical nightmare ! Thanks again
 

mrrsm

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There is a "Legendary Member" named "The Roadie" who has given so much to our understanding of these vehicles and who, unfortunately... no longer posts over here at GMT Nation...and while on another site... He offered this help on the problems involving the LGM, When you read his posts alongside the other folks who are in trouble.... Read Everything First because his solutions often don't appear until the very exasperating end on many of these threads. You will find some "sketchy" Wiring Schematic via Chilton's at this link as well that might prove useful ...and even if the exact year/model of the vehicle being discussed may not match yours... as usual... GM seldom changes its "infra-structure under garments" so much as to make their relevance unrecognizable. It is a Damned Shame that you don't have a TECH2 to help you with your Module Diagnosis. There have been many incidents of "Flood Zone Vehicles" being scooped up for next to nothing and then transported to other states for the Used Car Market... invariably the suffer from serious electrical 'mysteries'... I hope this link...and a decent Point Light Probe (Scope-On-A-Rope) allows you to go after the likely suspect wires, connections, and grounds involved. It is paramount to read this material very carefully...and I am hoping they Bang a Solution over there at TV for you,,, where "The Roadie" was also a sterling contributor:

http://forums.trailvoy.com/showthread.php?t=66500
 

Chickenhawk

Member
Dec 6, 2011
782
Once you fix the starting problem, I think the gas gauge is unrelated.

Gas gauge is either stepper motor or fuel gauge sender unit in the gas tank. If the gauge goes to E when the key is off, it is a sender unit. If the gauge stops at random places on the dial, it is a gauge stepper motor.

If it's a sender unit, it requires dropping the tank and also replacing the fuel pump. If money is short, just remember to zero the trip odometer at every fill and fill before you hit 500 kilometres. (400 in winter.) I would also try a fuel system cleaner too. It has been known to work sometimes, and is cheap and easy.

Whe using a fuel system cleaner, make sure it has "PEA" in it, and follow the instructions exactly. Do not use too much. Put it in your tank while filling, and in the proper amount. If you need more, don't mix it stronger; put it in two tanks back-to-back. Follow the instructions, and make sure you use only cleaners with PEA. (Techron, Gummout with Regane, Redline SI-1, etc.)
 
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mrrsm

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On behalf of the OP... The Battery Issues have been thoroughly covered in this Thread at Post #51, Post #52, Post #53 and Post #56...
 
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Mooseman

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Dec 4, 2011
25,358
Ottawa, ON
He did put in a new battery. I say we go from the most serious issue going down. Starting, or the lack thereof, is the main problem and I have a hunch it's related to the Park/Neutral safety switch for two reasons: you can't pull your key in P and your PRND321 indicator doesn't work. Either that or the shift cable may need adjustment.

Let's fix one thing at a time.
 
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Adjustso3

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Dec 10, 2017
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Hello guys. Yes I would really just like the truck to start and run. I would be happy with that lol. Is the Park/Neutral safety switch what’s on the tranny or on the shifter just to make sure we are talking about the same part.
 

Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Hello. I think I’m going to remove the entire center console tomorrow if my back will cooperate with me and the weather. Is that large blue connector for the rear controls and is there a special way to unsnap it ? With it being in single degrees outside I don’t want to force it or break anything. Is the shift interlock that’s on the shifter adjustable or is it just a bolt on part ? The reason I’m asking is because it has to be something “shifting” related because of the way it stalled and stopped when I moved the shifter into drive from park. This is the only thing that makes sense to me. The truck will crank if I jump the starter relay and if I jump the posts on the starter solenoid itself. It will “only” crank this way and not run. I just wanted to add this to observations. I’m definitely going to have to become a paid member here to help support all the help I have been receiving on this site. You guys have no idea how much I appreciate everybody’s valuable time.
 

Mooseman

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Dec 4, 2011
25,358
Ottawa, ON
I don`t think the solenoid/switch on the shifter is the issue. I think it's the Transmission Range Switch:

The transmission range (TR) switch is part of the park/neutral position (PNP) and backup lamp switch assembly, which is externally mounted on the transmission manual shaft. The TR switch contains four internal switches that indicate the transmission gear range selector lever position. The PCM supplies ignition voltage to each switch circuit. As the gear range selector lever is moved, the state of each switch may change, causing the circuit to open or close. An open circuit or switch indicates a high voltage signal. A closed circuit or switch indicates a low voltage signal. The PCM detects the selected gear range by deciphering the combination of the voltage signals. The PCM compares the actual voltage combination of the switch signals to a TR switch combination chart stored in memory.
 
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Chickenhawk

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Dec 6, 2011
782
On behalf of the OP... The Battery Issues have been thoroughly covered in this Thread at Post #51, Post #52, Post #53 and Post #56...
Thanks! For some reason, I missed a whole wack of posts. When I click on page 2 at the bottom, it returns me to page 1. This is why I thought the battery wasn't covered yet. Glad you folks are on top of it!
 
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mrrsm

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Okay... I've repeatedly covered or referred to the possibility that the Park Neutral Switch is either FUBARed... or simply needs re-adjustment WITHOUT THE NEED TO ACTUALLY REMOVE IT OFF OF THE TRANSMISSION... OR HAVING TO UNPLUG THE TWO CONNECTORS. At close to 4 Minutes into this GM 4L60E segment of a lengthy Re-Build Training Program... You will be able to see a GENERIC PARK NEUTRAL SAFETY SWITCH on the side of a 4L60E Transmission like yours... that is still mounted on the Driver's Side of the Transmission. Other than some minor differences in the Electrical Plug design shown on this video... THIS one is essentially identical to the one we want you to focus on as you next thing to do. If you Download and Watch this video segment from 4:00 onwards... as often as needed to become very familiar with that PNS switch... YOU JUST NEED TO KNOW WHERE TO LOOSEN THE TWO 13MM MOUNTING BOLTS.... AND THAT ACCESSING THE ONE 13MM BOLT HEAD ON THE ONE TOWARDS THE REAR WILL REQUIRE YOU TO REVIEW THE VIDEO IN POST #47 OF THIS THREAD TO UNDERSTAND HOW TO GAIN ACCESS TO THESE ADJUSTMENT FASTENERS. This Film is Your Best Friend in Helping You To Understand What Follows:


You will have a very limited ability to Rotate this Switch.... But this will be sufficient in most cases to get the Internal Switch positioned correctly so that when the Shift Lever in the Cab is Pushed (BY YOU) All the way forward into the PARK Position... Then The Park Neutral Switch INTERNAL ELECTRIC CONTACTS MUST BE IN PERFECT AGREEMENT in order for the PCM to believe that the Transmission is NOT is any other Gear Position. The way to accomplish this is... After loosening the 13MM Fasteners...JUST ENOUGH to move the Switch Body Up and Down... or if you prefer...JUST LOOSE ENOUGH TO ROCK IT BACK AND FORTH ON THE CENTER STEEL ROD.... and with the Key Off in the Ignition ...You will want the Vehicle Elevated on Ramps and with the Rear Wheels Chocked.. Then....You will need your Wife to sit in the Driver's Seat and Turn the Ignition Key On or Off ...BUT ONLY AFTER YOU TELL HER TO DO SO and only after you have made VERY SMALL INCREMENTAL CHANGES IN THE POSITION OF THE SWITCH BODY... and You must do this until She is able to Start The Engine... and then Turn Off The Engine and be able to remove the Ignition Key. SHE WILL ALSO NEED TO REMEMBER TO KEEP HER FOOT ON THE BRAKE PEDAL.

----===YOU MUST STRESS TO HER THAT SHE IS NOT TO TOUCH THE SHIFT LEVER OR MOVE THAT LEVER OUT OF PARK===----

You will need to be UNDER the Vehicle from the Driver's Side to perform this Task. Take several 13MM Open End and Box End Wrenches down there with you to Loosen and later Tighten the TWO 13MM Fasteners. All You need to do from this point on is MAKE VERY SLIGHT ADJUSTMENTS TO THE PARK NEUTRAL SWITCH BODY AND INSTRUCT YOUR WIFE TO MOMENTARILY TURN THE IGNITION KEY ON AND OFF UNTIL THE ENGINE STARTS.... And if it DOES START.... YOU STOP! ...and whatever you do... DO NOT MOVE THAT SWITCH.... Just SLOWLY Tighten Down the TWO 13MM Bolts....and THEN YOU ARE DONE!

If You are UNABLE to Locate the "Sweet Spot" and get the Vehicle to START AND RUN and perform this enough times to have confidence that it will perform Normally... Then in all probability...THE PARK NEUTRAL SWITCH WILL NEED TO BE REPLACED. But... Let's Cross That Bridge When We Come To It!
 
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Adjustso3

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Dec 10, 2017
112
Buffalo, NewYork
Ok guys. My internet was down and I just now had a chance to see the site. I went outside to check for blown fuses under the hood as recommmended. I checked all of them with a meter. There was one fuse blown. It was fuse #10 which is labeled PCM B. 20 amp. When I replaced this fuse I turned the key forward and the cluster lit up as it should but now that little indicator was under the P for park. I turned the key forward to try to crank and nothing. As usual the key did not come out but now that little indicator was gone again. I checked that #10 fuse again and sure enough, it was blown. I only had a couple extra 20 amp fuses and after a couple attempts I’m now out of fuses and have to get more. As usual, it’s snowing like crazy again and as soon as it stops I’ll see if I can crawl under the truck to check that switch. The majority of my tools are about a two and a half hour drive away at a friends house because we were working on his car. All I have available is misc screwdrivers and a 1/4 socket set lol. Not even my jack so I’ll have to get a ride out to his house and pick all my tools. It’s always something in my universe it seems lol. Ok, if you guys still think I should loosen the park/neutral switch on the tranny after hearing this report I’ll figure out how to get my jack and other tools to my house. And of course have to wait for it to stop snowing so I can work outside. Thanks again for everybody’s help.
I do have one more question. Does it matter which direction the starter relay is installed ? It can be installed two ways. I just want to make sure it’s installed correctly if it matters. Thanks again
 
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mrrsm

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The PCM... Jesus Wept...

Since that #10 (20 AMP) Fuse leads us to the PCM, before doing anything else on any other circuit, the PCM will need a very close inspection for any Cut Harness Wiring. On a prior occasion, a while back... I posted the entire PCM Wiring Harness Plugs Diagrams ...so as soon as I can locate them ....I'll drop them into this post with and edit to that link so you can Download them and print them out.

EDIT:

Here they are... Post Message #6

https://gmtnation.com/forums/threads/chasing-gremlins.16430/#post-521349

It will help to get an Engine Harness schematic diagram to sort out the Electrical Path, beginning at the #10 Fuse to the PCM and checking things in an orderly manner. Later on... If it comes down to cases and the PNS still remains related to the issue... I would be curious to know whether or not your 4X4 Transfer Case Drive Shaft runs in very close proximity to the area where the PNS is located. The reason for this depends upon whether or not your wife inadvertently ran over anything on the roadway that might have gotten either wound around the Shaft or jammed in between and either impacted, cracked or damaged the PNS internally.

The question now is whether or not any cut wires to the PNS Wiring could cause Dead Short to the PCM and immediately Burn Out that Fuse when the energy is "Keyed" to the RUN and START positions. If this turns out that this is so, then the Front Drive Shaft might be in the way of performing an easy PNS R&R and this will complicate this repair a great deal. Given the present weather conditions and in consideration of your Injured Back... which. mind you... is something I have absolutely NO trouble identifying with ...I too would be very reluctant to tackle this job in the Deep Snow. Nonetheless ... it still be necessary to at least inspect that entire area down there ...just to be sure.
 
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Adjustso3

Original poster
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Dec 10, 2017
112
Buffalo, NewYork
As always, thank you for the reply MRRSM. I’ve been googling along about this #10 fuse. What I believe I’ve read is that it handles the PCM and the fuel pump circuit. The only person who was driving it was me and I didn’t run over anything. I just want to add that since there is a lot of salt used in the winter around here I frequent the local Delta Sonic car wash to keep the TB clean and get that salt off. Just another observation a little while back was when it was really cold out, the key would have to be turned over and over and would eventually crank and fire right up. Driving it throughout the day it would be fine until the next morning. When it did kinda warm up ( above 32 ) it would crank on the first try. I’m beginning to think water may be the culprit here. Or should I say water that has turned into ice preventing some electrical connection possibly under the TB. I wish I had a heated garage to troubleshoot but unfortunately only have a driveway full of snow. I also read somewhere on here of a guy having almost the same problems as me that ended up being a fuel pump. I cannot hear mine but don’t remember hearing it before when it did run fine. Maybe it’s time to light a fire under it to warm it up and “hope” it doesn’t catch on fire LOL ! I almost wish there was an affordable guy with a Tech 2 that could diagnose this because it’s really driving me crazy. Thanks again and if you think of anything else please let me know.
 

Mooseman

Moderator
Dec 4, 2011
25,358
Ottawa, ON
Looking at the schematics, all I see for that fuse is it's the main 12V+ supply to the PCM. If it blew, it's for a reason. As @MRRSM said, you should check the wiring before replacing the PCM. However, the PCM is a relatively easy part to replace and they are starting to show up in pick-a-part yards now and relatively cheap. All you need is to get a PCM from a same year truck, preferably with the same gearing as yours (check your and the donor truck's glove box sticker for the Gearing RPO codes). Then you just need to swap the PCM out and do the Security Relearn. No tools required for your 2006.
 

Adjustso3

Original poster
Member
Dec 10, 2017
112
Buffalo, NewYork
Thank you for your reply Mooseman. I’m not sure if it matters or not but my TB is a 2003. Is the PCM the computer that is located in the air intake ? I just wanted to be sure. I’ll have to look up that security relearn and see if I can find another PCM.

I just did an inventory search for the scrap yard in the area. It appears they have pretty much every year TrailBlazer in the yard but a 2003. They have many 2004 models and a couple 2002s along with the rest of the years. Will only a 2003 Work ? If so, would an Envoy Work ? I have not searched the Envoy availability but was just curious. Thanks again for all the help.
 
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