Intermittent battery drain - '06

[4WDTRK]

The BCM ground is on the body mount on the frame rail, under the driver's door hinge. There are two or three critical grounds there; remove, clean, and tighten. Protect with paint or some kind of protectant.

Here's a zoomed diagram of that area; the attached PDF can be expanded for better clarity. (From the GM Upfitter's Guide)

View attachment 390340

Thanks I'll take a look! Does anything need to be removed to access the ground?

 

[rockola1971]

Thanks I'll take a look! Does anything need to be removed to access the ground?

Nope. They are right there on the chassis. Crawl under and look up at the chassis and you will see wires running right to the chassis up near where the firewall starts.

 

[MassHoe04]

Phot is blurry... I could get my phone camera to not do timer countdown.

Anyway, there are two ground points on the chassis. As described, they are on the driver's side just behind the front wheel. More or less in line with the A-pillar/door hinge.

Look on the wing that stick out for the body mount.

Mine don't look it, but I did clean the contacts. I do need to re-clean and cover with paint or primer in the spring.

These grounds are critical for the BCM and other electronics. Bad contact at these points can cause all kinds of strange behavior that can drive owners crazy in tracking down the source.

 

[4WDTRK]

Awesome @MassHoe04 thanks so much for pic!! I'm going to definitely pull and clean mine this weekend! That would be awesome if it was such a simple fix and I can get past this!

 

[Fless]

When I cleaned mine one of the two bolt holes was stripped so I used a washer and nut on one side.

 

[MassHoe04]

When I cleaned mine one of the two bolt holes was stripped so I used a washer and nut on one side.

Great tip!
I was actually surprised how easy the bolts on mine backed out.

My frame is not the cleanest one on the road and they came out fine. Even after a soak, the rusty bolts were squeaking on the way out. The threads still looked good.
A little 3-in-1 on the threads going back in to help clear out the rust in the threads and good to go.

 

[4WDTRK]

Yea mine has been garaged it's whole life pretty much. I do drive it a lot in wet weather, but I'm in Socal so we don't really get bad winters.

 

[4WDTRK]

I cleaned the grounds since it was easy to do, but no change in symptoms.

 

[4WDTRK]

I've done some testing and plan on replacing my cluster soon, though I'm not sure if it's the whole problem or not. What I've found is that when I'm measuring a draw of about ~1.1 amps at the negative battery cable, I then do a drop voltage test of the IPC/DIC fuse which shows about 300 milliamps. Obviously this isn't the whole load, but it's enough to kill the battery alone. When I pull the fuse the results are consistent and I only lose the 300 milliamps.

When I reinsert the IPC/DIC fuse the entire draw will go away and I'm back to normal. So pulling and reinserting that fuse must be resetting some component.

It's really a head scratcher. I'm just going to order another cluster soon and cover that base. I feel like I'm shot gunning it a bit, but I'm tired of dead batteries.

 

[Fless]

Pull the cluster and drive it like that, but watch your speed.

These clusters can suffer from "silver migration" around the solder joints, causing parasitic draw, so you could disassemble the cluster down to the circuit board and clean it with isopropyl alcohol and a toothbrush. Search for that term here, or Google it.