03 yukon electrical issues

[bob c]

help please!!!!! 03 yukon 5.3 all the bells. with engine off key in run position everybody is happy. start the engine and i loose all the gauges except tach and speedo. also loose windows and locks, radio display. climate control displays but will not engage compressor. abs light illuminated. put bcm and pcm in another vehicle and all is good. checked all the grounds i can find. any ideas? bob

 

[rockola1971]

HaHaHa electrical gremlins. Gotta love em. If I understood your post correctly you stuck your BCM and PCM in another vehicle and all worked fine without the symptoms you experience in your Yukon. This sounds alot like a common ground problem group of symptoms caused by the ground on the firewall directly behind the engine. You gotta look for it, its there or it should be! Just because it looks ok, pull it. Clean it and the firewall metal where it attaches along with the opposite end of the ground wire. It also sounds like you may have something else going on with a different ground but try the firewall first.

 

[bob c]

thanks for the reply. i have already addressed that one by removing the wire from the head and soldering an extension wire to the end so that it reaches the firewall post on the driver's side where the braided ground runs to the engine. ohm meter confirms good ground.

 

[rockola1971]

Checked wiring harness ground from BCM?

 

[bob c]

where is that ground? i may have already got to it. thanks for the help

 

[Steven781]

Did you ever find out the problem? I'm having this EXACT issue with my 03 SLT no front windows,door chimes,no key fob,no 4x4, no retained power accessories. I'm at a loss