Chevrolet Repair Questions? Ask a Chevy Mechanic for Answers ASAP
Hello, my name is***** body control module is what operates everything you mentioned and would be the reason for these problems. A new body control module needs to be reprogrammed to vin at dealership. Module + Installation is about a $500 job at dealership. Let me know if you have more questions or if there is anything else I can do to help. Thanks.
No problem, let me know how it goes. Thanks.
How did problem start? Thanks.
Does the engine turn over?
Have you tested for spark and injector pulse? Is your scantool capable of checking BCM codes or only PCM? Thanks.
There are a few different modules in the vehicle and some scantools can read codes in all the modules but most of the cheap ones can only check PCM codes. I'll open question up to see if someone else has some ideas, I think a scantool capable of reading all modules would be beast at this pont.
HI there. I am Cam. Give me a minute to check what you have looked at so far.
Ok, Do you have anything aftermarket installed like a remote starter?With the security light staying on, what fuse do you pull to get that light to go out?
Sure thing. Start in the truck and work your way out.
Ok, if you pull the cluster or radio out, what happens?
Ok radio fuse in or out, the security light does stay on still? I though that one made it go out.
If you unplug the cluster, put the fuse in, what happens?
Remove the instrument cluster. It is als powered by the radio fuse.
Ok, this does suggest we need codes. BLUEDRIVER is a device, 99$ sold on amazon reads all system codes.
Does your scanner have a light to indicate if it's getting power?
Ok, check the CIGAR fuse. It may not have power.
Do the top centre pins (2) of the data plug have a ground?
Ok so this gets very difficult. there is a splice pack in the harness behind the dash near the plug. Its #3 in the first picture. Pull the centre pin out and then connect manually the terminal for the Body Control Module (BCM) and Powertrain Control Module (PCM) only and see what happens. Then connect the pin for the plug and each module and probe for codes with your scanner. The pinout is also attached. If you find a module that is killing the data line, let me know and I can direct you on its location and carry on.
Was the BCM replaced yet?
Installed, setup and programmed or just installed?
It does need programming do theft system operation.
I have diagnosed one or two of these types of symptoms as bad instrument clusters. From my sources it seems to be a relatively common failure. If you're confident in taking it apart you will likely see a problem with the printed circuit board inside.
Could you possibly upload a picture of that spot and the opposite side of the PCB (Printed Circuit Board) in that spot that looks like it got hot? I will give you my opinion as to whether or not that could be your culprit. Throwing parts at things gets expensive quickly but at this point I'd be frustrated enough to swap one out of another truck. Do you have access to an ammeter (usually a function of a DVOM)? If so can try a parasitic draw test? I can find you the procedure.
My apologies. You probably noticed I'm new here. I'd like to help your sort this mess out but I don't see your email anywhere!
You can send photo's to***@******.*** or attach here.
I received your email. The discoloration you pictured probably wouldn't be enough for me to risk throwing a new cluster at it. I've seen that type of color on boards in cars that are heavily smoked in from time to time. Does your truck still start with a good battery? Did it start with a boost or good battery before the BCM was replaced? If it did and doesn't now I would recc. re-installing the original BCM. If it only doesn't start after it's been sitting then we need to do a few more tests with the multimeter. I can walk you through the procedure if need be.
Try unplugging the ignition switch while the key is off and out of the lock cylinder. If the lights and noises go away replace the ignition switch.
A problem with the ignition switch could be causing some computers to not power up. A problem with the instrument cluster could also be killing the serial data line which is a line used to establish a communication circuit between all of the different modules and computers on your truck. Your instrument panel is also known as an IPC or instrument panel cluster module: For what that's worth to you.
Oh and I also assumed that you checked the obvious (a bent pin where you're plugging your scan tool into the data link connector (DLC or OBDII port)
Alright John, Standing by. Hope we can get this thing figured out for you today.
Is it now a crank/no start, or is it a no crank condition? if you cycle the key in the ignition a bunch of time can you get any of the old symptoms to return?
If it is because of a no crank/no start condition you also need to be sure that the battery isn't drained again. But I'm guessing you've already verified it has a good charge.
Are you also saying that the Security and battery light don't come on at all during the initial bulb check when turning the key on? Or are those working okay after swapping for a fresh battery? Does repeated cycling of the key change any of the symptoms? if not what about wiggling the connector on the back of the IPC or tapping on the IPC with the heel of your palm or knocking on it with you knuckles (use a small rubber mallet in place of your knuckles if you're working in the cold to prevent injury)
Is it possible the vehicle was in a flood at some point in its life?
Does it start with the cluster harness unplugged? I would try that and plug it back in and look for a change in symptoms one more time. Then look for corrosion on the underside of the underhood fuse box if I couldn't prove the cluster or ignition switch bad. Finally after all of that I think I would kill it with fire.
Off the top of my head I'm not sure but I don't believe so. I'm just about at a loss here. My best shot in the dark guess would be throw a known working cluster in it and see what happens. but I'm not sure it will help your no start issue because if my memory serves correctly these trucks will start and run with the ICP unplugged. I'll opt out like the the others before me and keep following closely because I'm dying to know what you find on this thing. Good luck and please let me know if there is anything else I can do for you! And for what it's worth here is a copy of the five page schematic for your instrumentation. If you'll look closely you"ll see that all of your related symptom areas are somehow connected. But I also believe they're all connected through the ignition switch and other computers like the BCM
http://www.revbase.com/BBBMotor/Wd/DownloadPdf?id=18560 My apologies John here is the correct link. PDF Format
I have a another shot in the dark for you here. Measure the voltage drop at the plastic case of your battery from just between the two terminals. A dirty battery (Even one that looks clean) Can discharge itself across it's own surface robbing other functions of the power they need.
You're already tried ignition relearn procedure right? And I also found this TSB for you although but it seems like a longshot unless the ignition switch had already been replaced.
It seems nobody wants to help here. There's a couple things I'd like to know and one thing I'd like to tell you. One. Do we have injector pulse? You may need a noid light set (there are alternatives-i think a small bulb might work but do some research. I've always had the proper test set- and they can be cheap. You may have mentioned this, but ; Two. Do we have spark?
And for you to consider, I agree with Cam in getting it programmed. Call a different Chevy dealer and see if they can check the program in your bcm and update if need be. I'm not positive but I'm pretty sure they used these modules to manage trucks with different options packages.
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.
Do you still need help with this here as I see that have been several opt outs?
Let me know,thanks Pete.
Did you have a chance to look into programming again? This question is about to time out do this post should keep it alive. Keep us in the loop!