Well, I'm currently in the middle of a nitrous build on my cobalt and I was in the process of trying to locate a tachometer signal. Naturally I thought that I could source it from my gauge cluster (turns out that is not the case). I removed my gauge cluster and in the back there is a 16 pin connector that plugs in the back of it. I was probing each pin and revving the engine to try to determine which wire the signal was coming from. In my rush, I made an amateur mistake, and was using stranded wire to probe each terminal because my voltmeter probe was too large to fit inside the connector. I was placing the wire in one of the ports and one of the strands came off and I shorted between two terminals.

Afterwards I found the following systems to no longer function:

-Cruise control
-DIC (little screen in the gauge cluster, buttons on dash non responsive)
-CEL
-HVAC (fan works, will not control temperature)
-Three buttons under fan control (A/C, defrost, recirculate)
-Heated seats

I went and bought the factory service manual in PDF form that has all the wiring diagrams for the cobalt. It looks like I shorted between the "computer lines data system" which is tied to the BCM and PCM.

Anyone do this before? I am concerned after reading up on replacing the BCM that I will be forced to go to the stealership and get royally raped.


The most ironic part was that I was trying to install systems that were going to protect my car, and in the end it was what ended up breaking it....


P.S. - If anyone wants the service manual I would be happy to share it. Help in return would be appreciated.

 

with the car off pull out all the fuses and inspect to see if any are blown. Hail mary but hopefully

 

The systems you were going to install didn't end up breaking it, negligence did. If I were you, start checking fuses like ^^^ said. And trace those wires back to the relay. Might have fried several things with that stunt lol.

 

That sucks but if you shorted out the data connections you might have fried out the BCM and your stuck replacing it, also hope you didn't damage the PCM because that would be expensive. Next time get a tach signal from an injector or a coil pack. Also BCM isn't hard to replace.

 

I blew the fuse, at the BCM, supplying power to the gauge cluster, nothing else. I have wiring diagrams of everything and have traced the circuit.

 

I figured out I could get the signal off an injector after the fact. Never have done it before. You learn.

The BCM looks insanely easy to replace, however apparently it is a nightmare getting the proper part (because there are multiple part numbers / they modified that part between years). Also apparently the dealer has to flash it for some reason with a proprietary deal? Ever swapped one?

I would much prefer if it was all isolated to the PCM. I can grab one off ebay for $25. I have a Trifecta tune, so reflashing is a breeze. I am having a little confusion since GM uses the same computer in a large amount of cars and there are two numbers on th PCM. There is a part number and a "serv" number. I'm assuming one is a hardware number and the other is a software #. Just need to be 100% sure which one I need to match, drop the PCM in, flash it, and I'd be good to go.

 

I'm glad to hear it was a fuse! Yea I've replaced a few BCMs for friends and the dealer has to flash mainly for the RF ID off of your key. I work at a stereo shop and two of my cobalt buddies said they could do their own remote start/alarm install and ended up messing stuff. So instead of just the remote start I had to help them fix their mistakes and install their alarms; But hey, you live and you learn.

 

could i get a copy of that service manual in pdf?

vwatson@peerlessmfg.com

 

I blew a fuse and replaced it when I shorted out the harness. It wasn't until I was using the car, that I noticed all the issues. They are all still present.

 

thats sorta what i thought. gl bro

 

Well get ahold of your local wrecking yard, best of luck

 

Sent via Dropbox

 

Thanks Shawn!!!!!

 

any chance i could get that as well?

@gmail.com

 

Sent to EmperorJJ1@gmail.com

 

thanks bro ur the best. i got the notification on my phone and was like wtf. then remembered and said oh im an idiot

 

Could one of you fine gents drop me that pdf?

Monsuunknight@msn.com

 

shared. make sure to DL because im eventually going to move it from dropbox to drive

 

Thank you so much.

 

That sucks... GL