Okay so I found the Fix your BCM thread and I came to the conclusion that I had a bad BCM. Got a new one and replaced it today, thinking it would fix my problems with not being able to use anything electrical in my car. I cant use the windows, radio, power door locks, etc. at all without the car going into this mode where it cuts power to everything and just leaves the two turn signal arrows and the high beam symbol illuminated on my cluster. Everytime I open the door the horn honks sparatically and the locks, trunk release, and parking lights go crazy and everything doesn't stop until the door is closed. This happens with both doors and the hatch, my guess is whatever makes the dome lights come on makes the car go crazy. The car fires and drives fine, the only thing that happens is the radio turns on and off the whole time, I tried removing the radio after installing the new BCM and it didn't help. I thought for sure it was the BCM, well its not and I am pissed that its not since now I have no clue as to what it could be. Does anyone have any ideas??? Please help I have no clue what this could be.
If it happens all the time (ex. - when I do "X" then "Y" always happens) then it's easier to find than an intermittent problems (ex. - when I do "X" then SOMETIMES "Y" happens).
It find the root cause, do "X" to cause "Y" then start removing fuses one at a time, checking to see if "Y" still happens. Once "Y" no longer happens, typically because of the removal of one fuse, then you need to find the point where this secondary power source feeds the other items; that is the hard part. Look for areas in / on the vehicle where someone 'fixed' something (incorrectly), where the car was previously hit / damages, or where rubbing on the wiring harness has occurred.
I had a car with a power splice / crimp that went bad in the middle of the harness; once I found it, it was an easy fix, it just took a while to find it. Oh, a wiring harness diagram really helps! See shoebox's site if you don't have a real GM service manual.
Good Luck!
Quote:
Originally Posted by Blk98ls1
Okay so I found the Fix your BCM thread and I came to the conclusion that I had a bad BCM. Got a new one and replaced it today, thinking it would fix my problems with not being able to use anything electrical in my car. I cant use the windows, radio, power door locks, etc. at all without the car going into this mode where it cuts power to everything and just leaves the two turn signal arrows and the high beam symbol illuminated on my cluster. Everytime I open the door the horn honks sparatically and the locks, trunk release, and parking lights go crazy and everything doesn't stop until the door is closed. This happens with both doors and the hatch, my guess is whatever makes the dome lights come on makes the car go crazy. The car fires and drives fine, the only thing that happens is the radio turns on and off the whole time, I tried removing the radio after installing the new BCM and it didn't help. I thought for sure it was the BCM, well its not and I am pissed that its not since now I have no clue as to what it could be. Does anyone have any ideas??? Please help I have no clue what this could be.
Help w/ weird electrical problem!!!! 
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