Could This Be My Body Control Module Acting Up?

[Justinj360]

Hi,
My 2004 Yukon has done this twice now in the 15 months I've owned it. While driving each instrument cluster (like the radio, HVAC, rear view mirror, window and door controls and others) start turning their lights on and off intermittently. While this is all going on I start getting messages like "service stability", "service 4WD", "service tire monitor". The first time it happened I had to get to work so I parked it at work and I noticed the radio wouldn't shut off when I got out. It killed the battery by the time I got off work. Then it didn't happen again until today. (That was about a year ago).
My first guess is the BCM. What do you guys think? If that's what it is how much would it cost to replace or reprogram at the stealership? Thanks for your help.

 

[OR VietVet]

May also be a ground problem. Check them all under the hood and along the frame/engine area. But the BCM is a good guess.

 

[Justinj360]

May also be a ground problem. Check them all under the hood and along the frame/engine area. But the BCM is a good guess.

I'm hoping it's just the grounding! Would you mind telling me where the most common grounding points are? I'm not too familiar with the electrical.

 

[OR VietVet]

You will find them at the engine block with several wires attached there, firewall area, underside of frame at each side of engine back toward the firewall. General areas. Years and models change them. It is a hunt procedure and check for broken, dirty, corroded and/or loose.

 

[Justinj360]

Okay I'll look around for them first thing tomorrow! Should I try and clean up under the bolts with a grinder so they have a good clean connection? I appreciate the help!

 

[OR VietVet]

Yes or just sand paper.

 

[Justinj360]

Well over night I left the battery disconnected and then this morning I found a couple grounds along the frame underneath the driver and cleaned them up. It looked like they had paint underneath them and there wasn't much metal on metal contact. This afternoon I did some driving and it was like there wasn't ever a problem, just like the first time this happened. I guess I'll just have to wait and see when this thing comes back. Or maybe it was those couple of grounds and it's fixed now. Who knows...

 

[OR VietVet]

There will be more grounds than what you found. Keep checking and address as needed.

 

[SLCHOE]

There is a ground stud on the driver side firewall. It should be a braided flat wire.

Take that off and clean all of the surfaces with sandpaper. Reinstall. This is your body ground. This is what the BCM ties into.

 

[Justinj360]

There is a ground stud on the driver side firewall. It should be a braided flat wire.

Take that off and clean all of the surfaces with sandpaper. Reinstall. This is your body ground. This is what the BCM ties into.

I'm having trouble locating that ground you're talking about. Can you see it in this picture? And is that the BCM under that bracket on the right?