Thanks for that tip. This truck has made me create some new curse words ! LOL ! I just want to take a peek under there and see if anything is burnt. I’m a little worried since I smelled burnt wire when I jumped the fuel pump relay. I have a new ACDELCO ignition switch on the way and will try that first before I start tearing things apart. Maybe the last ACDELCO switch was bad. Thanks again.
Electrical help needed
- Thread starter Adjustso3
- Start date
Hello again. Does anybody have an idea why my TB cranks now as soon as I put the key in the accessory position since I jumped the fuel pump relay ? Yes I did install a new ignition switch a month or so ago and experienced the key not coming out when the key was turned back. It did function as it should though. Would a faulty “new” switch cause this to not let the key out and then a month later cause continuous cranking as soon as the fuel pump relay is put in ? This just makes no sense to me.
You have done the Ignition Switch R&R already… but for a cross-check on procedures… verify them with this video:
The other component that is intimate with the Ignition Switch … is the Ignition Key Tumbler. GM Dealerships and (Parts Direct?) sells a Replacement Tumbler and Key Set. With some slight variations to your own for the removal of the fascia, this video shows how to pull and R&R the Key Tumbler… Just In Case there is something mechanically wrong with the internal mechanism of yours that is causing the settings for Off, On/ACC and Start/Run to fail:
The other component that is intimate with the Ignition Switch … is the Ignition Key Tumbler. GM Dealerships and (Parts Direct?) sells a Replacement Tumbler and Key Set. With some slight variations to your own for the removal of the fascia, this video shows how to pull and R&R the Key Tumbler… Just In Case there is something mechanically wrong with the internal mechanism of yours that is causing the settings for Off, On/ACC and Start/Run to fail:
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Thanks MRRSM. Thanks for the videos. I’ve watched those exact ones many times to see if I’ve done something wrong. Thinking back, the key not being able to be removed started with the new ACDelco ignition switch, but it did operate in accessory and crank the engine when turned all the way forward. I’m not going to replace anything until the new switch comes in. I was just wondering if something could of “melted” together when I jumped the fuel pump causing the constant cranking condition. I did look up at the cylinder as you suggested but didn’t really see anything obvious out of whack. This new problem just doesn’t make sense to me other than the fact that the replaced switch failed or some wires burnt together somehow.
well.... you have too be a bit more specific as opposed to "jumped the fuel pump" which leaves much to the technical imagination. What connections specifically did you connect to what? Further, IF you didn't check the resistance of the circuit that was about to receive some voltage from "somewhere" (and whether that source was fused), then it is quite possible "significant current happenings" may have occurred which may have caused any amount of unknown results which means you are left with a lot inspection / checks (meter or otherwise) to find out the current state of things.
As @Mooseman has mentioned... if there is a Dead Short present ...there is a very real possibility that so much Amperage remained connected to the circuit ... perhaps it was working long enough to Heat the Wires up enough to melt their protective sheathing and insulation from the start of the Relay Bypass and on down ...following the various wires involved in the circuit... and ending inside of the Fuel Tank. If the wires and their connections were Boiling Hot under the Liquid Gasoline... the only thing that would prevent something igniting down inside there is that Liquid Fuel Cannot Burn in the absence of Oxygen and neither can a Super-Saturated Gasoline Vapor Filled Container catch fire without having enough O2 to burst into flame. Let us all hope things are not this bad as this ...and will not become so. So before beginning... Please... PUT BACK ALL OF THE PROTECTIVE FUSES AND RELAYS TO THEIR ORIGINAL STOCK CONFIGURATIONS BEFORE DOING ANYTHING ELSE.... AND DOUBLE CHECK THEM.
I am going to urge you to watch this next video... and then download it and SLO-MO the parts where the VOP is using his "Scope On A Rope" to check EACH AND EVERY IGNITION WIRE FOR CONNECTION AND CONTINUITY and at least determine the integrity of the EACH INDIVIDUAL WIRE using both the LIGHT PROBE and then repeat this action using your DIGITAL MULTI-METER for these issues. Take some good notes after drawing out a Simple Wire Diagram of the Wiring under the steering column feeding the Ignition Switch ... and document what each wire does after using BOTH TEST METHODS.
I would also seriously urge that you not perform any of these tests if your vehicle is parked inside of your garage... I believe it is not...but I am just mentioning it now in case you moved it back inside to get out of the bad Weather. Be prepared with a decent ABC Fire Extinguisher and have an 8MM Ratcheting Battery Terminal Tool at Hand at best in the advent that you need to suddenly cut off the Battery Power to the Vehicle... and at Worst... Keep a Sturdy Pair of Cable Cutters, Metal Tin-Snips or A Pair of Sharp Pruning Shears nearby in the unlikely advent that you will need to suddenly Chop and Separate the Battery Ground Cable and Stop things anything electrically dangerous from going completely sideways on you.
I am not suggesting that these things WILL happen... but at the Very LEAST you will be prepared to act quickly if something does go seriously wrong during your investigative efforts. Please Remember... Do Not to get too focused and distracted while working away and to use ALL of your senses when doing these things. Besides LOOKing at everything... LISTEN for any Sizzling or Crackling sounds and if you detect ANY SMELL of Burning Odors.... you will know to STOP immediately and Prevent the Battery from continuously Feeding the Truck with Power that will NOT STOP if you cannot switch off that Ignition Switch.
And in support of @budwich 's initial suggestion to dope out the Amperage Draw under the Fuse Box... South Main Auto also has another video in which he uses a FUSED DMM and his "Scope on a Rope" to diagnose a FUEL PUMP DRIVER MODULE THAT IS DEAD SHORTED TO THE TRUCK FRAME DUE TO SALT WATER INTRUSION... Nonetheless... Regardless of the vehicle being different and the Component Failure being different..... Watch from around 12:30 on in this Video as he employs a FUSED Test Wire set up to prevent destroying his equipment while he measures that Short Circuit as having around a 30 Amp Draw... which winds up repeatedly Blowing his 20 Amp In-Line Wire Fuse . So the value of this Video is that he will show YOU What Tools to use... Where to check the Circuit at the Fuse Box and How to do this Activity and draw the correct conclusions from the evidence:
I am going to urge you to watch this next video... and then download it and SLO-MO the parts where the VOP is using his "Scope On A Rope" to check EACH AND EVERY IGNITION WIRE FOR CONNECTION AND CONTINUITY and at least determine the integrity of the EACH INDIVIDUAL WIRE using both the LIGHT PROBE and then repeat this action using your DIGITAL MULTI-METER for these issues. Take some good notes after drawing out a Simple Wire Diagram of the Wiring under the steering column feeding the Ignition Switch ... and document what each wire does after using BOTH TEST METHODS.
I would also seriously urge that you not perform any of these tests if your vehicle is parked inside of your garage... I believe it is not...but I am just mentioning it now in case you moved it back inside to get out of the bad Weather. Be prepared with a decent ABC Fire Extinguisher and have an 8MM Ratcheting Battery Terminal Tool at Hand at best in the advent that you need to suddenly cut off the Battery Power to the Vehicle... and at Worst... Keep a Sturdy Pair of Cable Cutters, Metal Tin-Snips or A Pair of Sharp Pruning Shears nearby in the unlikely advent that you will need to suddenly Chop and Separate the Battery Ground Cable and Stop things anything electrically dangerous from going completely sideways on you.
I am not suggesting that these things WILL happen... but at the Very LEAST you will be prepared to act quickly if something does go seriously wrong during your investigative efforts. Please Remember... Do Not to get too focused and distracted while working away and to use ALL of your senses when doing these things. Besides LOOKing at everything... LISTEN for any Sizzling or Crackling sounds and if you detect ANY SMELL of Burning Odors.... you will know to STOP immediately and Prevent the Battery from continuously Feeding the Truck with Power that will NOT STOP if you cannot switch off that Ignition Switch.
And in support of @budwich 's initial suggestion to dope out the Amperage Draw under the Fuse Box... South Main Auto also has another video in which he uses a FUSED DMM and his "Scope on a Rope" to diagnose a FUEL PUMP DRIVER MODULE THAT IS DEAD SHORTED TO THE TRUCK FRAME DUE TO SALT WATER INTRUSION... Nonetheless... Regardless of the vehicle being different and the Component Failure being different..... Watch from around 12:30 on in this Video as he employs a FUSED Test Wire set up to prevent destroying his equipment while he measures that Short Circuit as having around a 30 Amp Draw... which winds up repeatedly Blowing his 20 Amp In-Line Wire Fuse . So the value of this Video is that he will show YOU What Tools to use... Where to check the Circuit at the Fuse Box and How to do this Activity and draw the correct conclusions from the evidence:
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Thanks once again for the replies guys. To Budwich - the points I jumped were 87 and 30 of relay 41 for the fuel pump. This discussion started back in the mid 90 posts of this thread. No I did not check with my meter when I jumped the fuel pump because my meter was still in the hands of a friend. Yes, not checking it first with a meter was a major mistake on my part. Another mistake was throwing out the old ignition switch. It’s ok because another ACDelco switch is on the way and if has the same results will be a spare. To MRRSM, thank you very much for the info. I will draw up a little diagram and take note of the results and compare them with the video. I finally have my meter back and a test light so I’ll be able to perform the tests. If there is no rain or snow I’ll be checking things out in the afternoon. Thank you for sticking with me as I appreciate all your time.
NP... We are ALL in this Deep Hole with you... Hopefully handing out Ladders and Climbing Ropes...and NOT Shovels... :>)
ok.... you are likely wasting your time doing much else than focusing on the ignition key issue. Pull the fuel pump relay until you can operate your ignition key per spec / function. That means in key off, it should be removeable with out any issue. If it can't be done, address this completely. Then move the key to run. Get your meter and check the powering points that should be powered in run. From there move to the start position. Once this has been checked, think about what you have done / seen in terms of the wiring / blocks / etc for any indications of issues. Finally, measure resistance of the wiring headings to the pump (at the removed fuel pump relay socket). Next, with the relay removed, now measure / check for voltage at the same point in the socket with key in ON and lastly in start. There should be no difference..... it should be zero. Go from there.
Hello again guys. I received my new ignition switch and the TB still cranks continuously as soon as I turn the key forward to accessory. I did manage to get to the junkyard and now have another fuse block. I guess it looks much different when pulled apart than what I was thinking it would look like. I thought there would be a bunch of wires underneath but now see the blocks with wires that are snapped in place. I guess the first thing now that I need to do is get the TB to stop cranking continuously as soon as the key is in accessory with all fuses and relays in place. As stated before, this only happened after I jumped the fuel pump relay #41 (87 and 36). Im at a total loss and not sure where to start. With all the electrical problems, what and where should I start and do ? As always, many thanks in advance.
This problem sounds like a "Stuck Solenoid" on the Starter... and the distinction here from just being "An Ignition Switch Problem"...is that even if you return the key to the "OFF" position... it will NOT matter due to the simple, direct action design of the Solenoid-To-Starter Mechanism. Just think of the Ignition Key side of the Circuit as initiating "The Small Force" that controls whether or not the Starter begins to turn... The Small Force is the small amount of current-voltage that is necessary to activate the Electro-Magnetic Coil inside of the Solenoid that has a Ferro-Metal Rod with a Copper Contact Plate that can move outwards temporarily and allow "The Strong Force" of the B (+) Battery Power with as much as 700 Cold Cranking Amps to establish Contact... and surge with High Power through Plate and into the 10 AWG Wire and enter the Starter to get it going.
But... Ordinarily... this can only happen as long as the Key is held in the "START" position, ensuring Coil Activation drives the Pin-Plate and Contact Plates of the Solenoid together, completing the circuit that allows that Heavy Current to Flow. If you have a Solenoid with a Mis-aligned Pin or a Weak Return Spring designed to pull the Contact Plates apart once the Key is moved to the OFF/ACC position... Then ALL of the (+) Power coming from the Battery will continuously Flow through the Starter with enough energy to soon melt the innards. If the "Starter" won't "STOP" ... and releasing the Key does not make it do so... your only recourse then would be to either Cut the Ground Battery Cable or to Quickly Disconnect the Cable Connector from the Negative Battery Terminal. If, as you say, you have replaced the Ignition Switch with an OEM ACDelco version and this problem persists... either you STILL have a Misalignment of the Gears underneath the Steering Column... or... your Ignition Tumble is cracked or damaged inside the column and is not committing the rotation completely enough in either the ON or the OFF Positions to function properly... or... Your Solenoid is Malfunctioning as the aforesaid paragraphs explain.
The R&R of the Entire Starter with an OEM Flavor would be required if you can Test out the problem...without using the key in the Ignition to initiate the action...instead using a "Push Button" Remote Starter Cable Pair with Insulated Alligator Ends to attach to the "The Small Force" Solenoid Terminals to cause the Starter to Engage. If this is done... and the Starter Runs continuously without engaging the Key in the Ignition... then the "Sticking Solenoid" is The Culprit.... Perform the Starter/Solenoid Combo R&R as they are considered One Unit. But if the Starter turns over ...and as soon as you release the "Push Button" ... it STOPS... Then you are right back in the mix of having to investigate what the Hell is going on with your Ignition Circuit-Steering Column as your point of Focus. Please do not ignore the possibility that the Key Tumbler should be looked at in all of this, too. The Local GM Dealership sells the Keys/Tumbler as a Set.
One last thought... Einstein once said, "Doing The Same Things.. The Same Way...Each and Every Time... and Expecting a DIFFERENT result... is the First Sign of Insanity..." Please examine each and every step you have done so far and look for ANY possible mistakes you might have made if you did your repairs or R&Rs in the identical manner ...each and every time.
You can pick up a "Push Button Starter Switch" on Amazon for just a little money:
https://www.amazon.com/dp/B00OPVYHZ4/?tag=gmtnation-20
But... Ordinarily... this can only happen as long as the Key is held in the "START" position, ensuring Coil Activation drives the Pin-Plate and Contact Plates of the Solenoid together, completing the circuit that allows that Heavy Current to Flow. If you have a Solenoid with a Mis-aligned Pin or a Weak Return Spring designed to pull the Contact Plates apart once the Key is moved to the OFF/ACC position... Then ALL of the (+) Power coming from the Battery will continuously Flow through the Starter with enough energy to soon melt the innards. If the "Starter" won't "STOP" ... and releasing the Key does not make it do so... your only recourse then would be to either Cut the Ground Battery Cable or to Quickly Disconnect the Cable Connector from the Negative Battery Terminal. If, as you say, you have replaced the Ignition Switch with an OEM ACDelco version and this problem persists... either you STILL have a Misalignment of the Gears underneath the Steering Column... or... your Ignition Tumble is cracked or damaged inside the column and is not committing the rotation completely enough in either the ON or the OFF Positions to function properly... or... Your Solenoid is Malfunctioning as the aforesaid paragraphs explain.
The R&R of the Entire Starter with an OEM Flavor would be required if you can Test out the problem...without using the key in the Ignition to initiate the action...instead using a "Push Button" Remote Starter Cable Pair with Insulated Alligator Ends to attach to the "The Small Force" Solenoid Terminals to cause the Starter to Engage. If this is done... and the Starter Runs continuously without engaging the Key in the Ignition... then the "Sticking Solenoid" is The Culprit.... Perform the Starter/Solenoid Combo R&R as they are considered One Unit. But if the Starter turns over ...and as soon as you release the "Push Button" ... it STOPS... Then you are right back in the mix of having to investigate what the Hell is going on with your Ignition Circuit-Steering Column as your point of Focus. Please do not ignore the possibility that the Key Tumbler should be looked at in all of this, too. The Local GM Dealership sells the Keys/Tumbler as a Set.
One last thought... Einstein once said, "Doing The Same Things.. The Same Way...Each and Every Time... and Expecting a DIFFERENT result... is the First Sign of Insanity..." Please examine each and every step you have done so far and look for ANY possible mistakes you might have made if you did your repairs or R&Rs in the identical manner ...each and every time.
You can pick up a "Push Button Starter Switch" on Amazon for just a little money:
https://www.amazon.com/dp/B00OPVYHZ4/?tag=gmtnation-20
It is unlikely that you have a starter issue. Your problem is either around the key switch (wiring there of) or wiring going to from the fuse block (engine comp). As posted previously in this thread, the schematic shows why you are getting the result (starter in run). Battery is always being sent to the starter relay. However, the relay gets its ground from the PCM ONLY when it "sense" that the key is in "start".... which alllows a "voltage signal" to show up at the PCM signalling it to ground the appropriate wire back to the starter relay ... which then cause cranking. As the schematic shows, this should NOT happen in run since it clearly show there is NO connection in the key switch between "run" and "start" (good thing as then your starter would always be on when the engine is running). Anyways, pull fuse 17 (start fuse) and turn the key to "run"... what happens.... there should be no starter action. IF this is true, your problem is back from the fuse block towards the key. IF it is not true, you likely have significant issues in and around the fuse block. Again, do not worry about going any further than fixing the cranking / key issue.
Having said all this, check the starter relay as its contacts could be welded. Still further, from my limited experience in playing with "recent" GM stuff, I have seen occasions whereby a relay can be put in "backwards" as the pin orientation does not prevent this (my limited experience.... dumb design)... but if this is possible here then the operating windings would now be completing the "start circuit" and result in starting attempt whenever the key is put to on. Hence check the start relay and confirm its orientation AND integrity.
Having said all this, check the starter relay as its contacts could be welded. Still further, from my limited experience in playing with "recent" GM stuff, I have seen occasions whereby a relay can be put in "backwards" as the pin orientation does not prevent this (my limited experience.... dumb design)... but if this is possible here then the operating windings would now be completing the "start circuit" and result in starting attempt whenever the key is put to on. Hence check the start relay and confirm its orientation AND integrity.
Mooseman
Moderator
There is absolutely no interrelation between the accessory circuit and the start circuit. I can't see how they could affect each other unless there is a dead short between the two. Even then, because you don't have it in the RUN position, the PCM would not have any power and should not be engaging the starter because none of the other PCM functions are on.
Just to clarify, you do not even turn the key to crank at all right? You just go to the first detent position ACC and it starts cranking by itself? If you are flicking the key to the START position, let go and it keeps cranking until it starts, this is a normal function. And the PCM also has two other protection features. If you keep holding in the START position after it has started, it disengages the starter and will not allow the starter to engage again if already running, even if you turn the key to START again. The other is in a no start condition where it will crank the engine for about 5 seconds and if it doesn't start, will disengage the starter unless you are holding the key in the START position.
Just to clarify, you do not even turn the key to crank at all right? You just go to the first detent position ACC and it starts cranking by itself? If you are flicking the key to the START position, let go and it keeps cranking until it starts, this is a normal function. And the PCM also has two other protection features. If you keep holding in the START position after it has started, it disengages the starter and will not allow the starter to engage again if already running, even if you turn the key to START again. The other is in a no start condition where it will crank the engine for about 5 seconds and if it doesn't start, will disengage the starter unless you are holding the key in the START position.
Thanks for the replies guys. Yes the TB cranks as soon as key is put into accessory position. One thing that I do remember just before this continuous cranking problem was I was making contact with the PCM B fuse and then disconnecting that fuse to try to figure out where a clicking sound was coming from around the PCM area or the PCM itself. It kinda sounded like a solenoid or a relay. That sound stopped and then I had the continuous starting problem. The noise was NOT coming from the fuse block. Is there anything in the PCM that will make a clicking noise when given power ? Keep in mind this is a junkyard PCM that’s in there now. I’ll also order that starter button and give that a try as well. Thanks again.
Hello all. I’m a little confused about the starter cranking on its own situation. Shouldn’t the starter only get voltage when the key is turned into the start position ? What is it that tells the starter to stop cranking and time out ? For some reason, this is what I think my continuous cranking problem is. Does this make sense ? Thanks again
In the Old Design... the Starter Circuit was much less complicated... but in the TRAILBLAZER & ENVOY SUVs... it is NOT like THIS:
...but it is LIKE THIS:
Nobody will EVER explain how this Starter Circuit works... Better than 'Drew (MAY03LT) So Download this Video to the Folder holding all of your other reference links and materials on this bizarre electrical nightmare ...so you can look it over often.
...but it is LIKE THIS:
Nobody will EVER explain how this Starter Circuit works... Better than 'Drew (MAY03LT) So Download this Video to the Folder holding all of your other reference links and materials on this bizarre electrical nightmare ...so you can look it over often.
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This will be my Third Visit to the Topic of Replacing the Ignition Switch… but for the Love of God… Please… Humor me once again and see if what you did when you R&Rd yours… resembles what this VOP (Video Original Poster) did… Step for Step… Exactly… and if this turns out to be the case… I am beginning to suspect that either your Harness(es) either have some cuts or shorts somewhere in the wire bundles… or the Harness Connectors are cracked ...or their in-dwelling Wire to Plug points are somehow making electrical contact and shorting to a Start Mode as soon as you put the Key into the Ignition:
Thanks again MRRSM. I totally agree with you that it sounds like I put that ignition switch in wrong or a tooth or so off. I did look at the tumbler with a flashlight with the switch out and the gear looked fine. I couldn’t find a perfect pic of the switch gears when the key is in the off position. To me it looks like the last tooth of the bigger gap is supposed to be almost out of sight. Just for giggles, can the teeth on the switch be alligned to start and the key held in the most forward position ? It almost sounds like all the switches and connectors have to be replaced with all the problems I’m having like the constant crank, shifter being able to me moved without the key, the shifter able to be moved without pressing the brake, and of course it not starting or hearing the fuel pump along with all the other electrical problems. I wish I had run a car fax on this truck because it sounds like a flood vehicle. Thanks again for the help. I’ll watch those videos until I know them word for word.
mrwitty_1
Member
- Jan 28, 2014
- 90
Is it possible to remove the ignition switch from the housing and operate it with a flat blade just to see if the switch was installed a tooth off ? This would eliminate the possibility of incorrect install and or shorted circuit. The main thing to remember in newer vehicles is that many switches do not control voltage but simply send requests to the ECM and BCM and other modules to activate the desired function.
Hello mrwitty1. That’s actually a good idea but I’m not sure if it would work like that. Maybe someone will chime in and give the thumbs up or thumbs down. I’m not positive but I might of tried that a while ago and it didn’t do anything. Does anybody have a clear pic of the position of the teeth on the switch when the key is in off mode where it kinda shows the location of the two large gaps on the gear ? I’ve done all kinds of work on vehicles over the years from rebuilding engines to brakes, but this Trailblazer has me so confused it’s like I don’t know which end of a hammer to use LOL.
Okay... "Murphy's Law" being what it is... If you can do the following five things... you may find some additional ideas on 'What Position the Ignition" teeth should look like prior to being installed:
(1) If you can stand the sound of the VOP's Irritating Voice
(2) If you can stand the sound of the Chirping Birds
(3) If you can stand the sound of the Fire Truck Sirens
(4) If you can stand the sound of the P47 "JUG" Fighter Plane Buzzing the VOP's House
(5) If you can stand the VOP's Nervous Gesticulations
...then MAYBE ...just MAYBE ...this Video will have some additional views of the Ignition Switch Teeth Alignment that perhaps look different from what yours appeared to look like during its insertion into the bottom of the Steering Column:
And here is yet another look at the situation involving the Park Lock Switch Solenoid and a jammed Up Ignition Key:
(1) If you can stand the sound of the VOP's Irritating Voice
(2) If you can stand the sound of the Chirping Birds
(3) If you can stand the sound of the Fire Truck Sirens
(4) If you can stand the sound of the P47 "JUG" Fighter Plane Buzzing the VOP's House
(5) If you can stand the VOP's Nervous Gesticulations
...then MAYBE ...just MAYBE ...this Video will have some additional views of the Ignition Switch Teeth Alignment that perhaps look different from what yours appeared to look like during its insertion into the bottom of the Steering Column:
And here is yet another look at the situation involving the Park Lock Switch Solenoid and a jammed Up Ignition Key:
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mrwitty_1
Member
- Jan 28, 2014
- 90
I have attached the removal and install of the ignition switch. I believe this may point you to why the key can not be removed and why you have the immediate crank when first turning the key. In my opinion the ignition switch is not in the correct position. Hope this helps.
Thank you very much for your reply. According to those instructions I HAVE been aligning the teeth of the ignition switch incorrectly. It show the large gap exposed and I have been setting it to where you can no longer see the large gap when the key cylinder is in the lock position. All the videos and pics I’ve seen show the last gap out of sight. Your instructions are the first I’ve seen where the large gap is so exposed. I have my fingers crossed that this is the problem. I am currently out of town with a friend who has serious medical problems and should be back in a few days. I’m really anxious to try your method ! Thank you very much !!!!
mrwitt 1, I do have a question for you. On page 5 of the instructions you provided it states.....Important: In order to reach a stop while rotating the lock cylinder housing gear you MUST push and hold in the solenoid on the electric park lock...... Is the electric park lock the solenoid which is located on the shifter in the center console ? With all the problems I’m having I just want to make sure I’m doing everything correctly. Can I ask you where you found these instructions ? I’m only asking because this source may help me with all the other problems I’m having with my TB. Thanks again and I appreciate all your time.
mrwitty_1
Member
- Jan 28, 2014
- 90
I don't remember ever removing the lock cylinder on any ignition switch installs. I have attached the park lock instructions which shows location. I to feel you have something going on with this which will prohibit the key being removed. Not sure if you had removed the lock cylinder or not. Best of luck.
Thanks for those instructions mrwhitty 1. No I have not removed the lock cylinder. Thanks again
Hello everyone. Unfortunately health issues got in the way for a while but I’m now back messing around with the 03 TB. After struggeling with strap bolts, the tank was finally dropped and crispy wires were found. The pigtail was replaced and a new AcDelco fuel pump was installed. Ok, now the PCM B fuse does not blow and the truck will now crank over and start up and run. The only problem is that there are throttle body codes and there is zero pedal response and it’s undriveable. Back somewhere in this thread it was suggested to replace the PCM to possibly solve the PCM B fuse blowing problem. A security relearn was done with a compatible PCM. Could this now be my problem with no pedal response ? I still have the original PCM. Should I just install that one and turn the key or do I have to do a security relearn and or case learn on the original PCM ? I now have no vehicle so all my eggs are unfortunately in the TB basket and with no money or a way to get to doctors appointments I’m going to have to do my best to get this truck driving again. If you think you have an answer, please help. Many thanks in advance.
If you're satisfied that you've sorted out the Shorted Wiring... it will not hurt to remove your (-) Negative Battery Cable... then after removing the Donor PCM ... blow the dust out of the Three PCM Connectors on you're original PCM (No Oily Spray Here...Canned Air or Shop Air will do) and after re-attaching it and the (-) Battery Cable ... Start the Vehicle and see how She behaves.
If you made no changes prior to its removal way back when... the OEM PCM should still be storing all of the old conditions you started with. But...If this does not work... then you will need to investigate the other components besides the PCM that if either Sketchy or FUBAR ...would cause it to go into "Limp Mode" :
(1) The Throttle Body Connectors/Wiring.
(2) The ACC Pedal and Connector.
(3) ...and if a later model TB/Envoy... the MAF and IAT combo sensor connectors and wiring.
If you made no changes prior to its removal way back when... the OEM PCM should still be storing all of the old conditions you started with. But...If this does not work... then you will need to investigate the other components besides the PCM that if either Sketchy or FUBAR ...would cause it to go into "Limp Mode" :
(1) The Throttle Body Connectors/Wiring.
(2) The ACC Pedal and Connector.
(3) ...and if a later model TB/Envoy... the MAF and IAT combo sensor connectors and wiring.
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Mooseman
Moderator
Hello again. Here are the codes with the doner PCM installed. P1120- TP sensor 1 circuit, P1275- APP sensor circuit, P1280 APP sensor 2 circuit. It starts right up now. The key will not turn back unless I push the little button.
Mooseman
Moderator
Long shot: Try disconnecting the radiator fan clutch connector. The throttle system and the clutch are on the same circuit and has been known to screw it up.
Then, I'd be looking at either the throttle body or the pedal sensor or their wiring. Try reinstalling the original PCM.
That is usually what happens when the battery is dead but since you replaced the ignition switch, I'd be looking at that as a cause or possibly not installed correctly.
Hello again. I disconnected the negative battery cable and I pulled the doner PCM. I then cleaned the original PCMs connector and the 3 wire connectors with CRC electrical cleaner spray. I let everything dry for an hour. Installed the original PCM then the 3 wire connectors. Then hooked up the negative battery cable. Got in and turned the key and she fired right up. The pedal now works as it should ! WOW was I shocked ! And very happy of course. Gonna check out that ignition switch to see if I can get that key to turn back and remove the key. This has been such a long journey but at least I can get around now. Thank you to everyone who helped. I appreciate each and everyone’s time. Now it’s time to start working on the remainder of the electrical gremlins. Just curious, any idea why the sonar PCM wouldn’t work even if cleared the codes with my scanner ? I’d like to have a spare PCM just in case. I don’t remember if it was from an 02 or 04 but the gearing was the same.
Mooseman
Moderator
It may have been for the wrong year. Or you didn't do a security relearn? Or it may have been defective. It happens. In any case, you got that part squared away. 
Hello everyone. The TB is finally running but I still have those other gremlins to deal with. There’s an AC clutch problem that was started in another thread. I’m trying to solve the key not turning back an release problem now. Im pretty confident I have the ignition switch aligned correctly with two different new switches. The shifter now locks up in Park like it should and can’t be moved out of park unless I push the brake. If I press the solenoid under the center consol. The key will still not turn back. Should I assume the only part left is the park/neutral switch on the tranny ? I hate shotgunning parts but all else seems fine. Any suggestions ?
Mooseman
Moderator
There's probably a solenoid for the key release. Look up the schematics and see which wires power it. See if power get to it.
Post #47 Covers the matter of "adjusting" the Park Neutral Switch rather than just replacing it:
https://gmtnation.com/forums/threads/wont-start-after-engine-swap.18641/page-2#post-562512
https://gmtnation.com/forums/threads/wont-start-after-engine-swap.18641/page-2#post-562512
Thanks for the reply’s guys. This thread has been going on for so long and is so lengthy. I’m happy somebody remembers lol. MMRSM, is the Park/neutral switch on the transmission one of the parts that can effect the key turning back and coming out ? Thanks again.
Mooseman
Moderator
Thanks for the reply Mooseman.This truck has my head spinning so fast I can’t think straight LOL