2006 2500HD Duramax - Electrical Problems

abadv8 · April 13, 2014

Good morning All,

I have an '06 Chevy Silverado 2500HD, LBZ, CCSB, LT3 truck, and it's giving me some grief. I had a bunch of intermittent issues all start at once. Below is a list:

1) Fuel, Temp, Oil, and Volt meter fail to off position.

2) Battery and ABS lights illuminate

3) “Service 4WD” message is displayed

4) Radio loses power or displays "LOCKED"

5) Power windows and lock do not work

6) Headlights turn on, even in full sunlight

7) Opening door does not always turn off RAP or IPC

8) HVAC controls still work

9) Security shut down happens sometimes (starts but dies 2 seconds later)

10) Heated seats do not work

11) Dome lights do not turn on when opening the door

12) Radio lights on with the ignition off (they were the only lights on in the truck)

13) Turning on the parking or headlights does not immediately turn on instrument lights (there is a 5-20 second delay)

14) Window switches may or may not be lit

15) Truck starts and runs fine (when it is not shut down by security system)

What I've found so far is some of the wires at connector C100 had been chewed by a mouse. I have cut and soldered to repair the bad sections. I have tried an ignition switch, BCM, and cleaning up some of the grounds (front left frame rail, under drivers door, G203 at A-pillar). Nothing seems to have made any improvement.

Other things that I've done are reverted to stock from level 4 with my PPE tuner, disconnected the Viper alarm system and XK01 data line interface. I've been running the truck this way for 6 years, so I doubt any of those are the problem. However, I wanted to eliminate them as a source of issues.

I was thinking that the BCM may be flaking out, but a replacement exhibited the exact same issues. Since this is intermittent, and happened suddenly, it made sense. However, after finding the chewed wires under the fuse panel, I'm not so sure anymore.

Any help that anyone can offer would be most greatly appreciated.

Thank you.

SouthCo · April 13, 2014

Might just be me but I can't see your list. I have a '07 LBZ so curious what your dealing with....

abadv8 · April 13, 2014

Does it show up now?

Fuel, Temp, Oil, and Volt meter fail to off position.

Battery and ABS lights illuminate

“Service 4WD” message is displayed

Radio loses power or displays "LOCKED"

Power windows and lock do not work

Headlights turn on, even in full sunlight

Opening door does not always turn off RAP or IPC

HVAC controls still work

Security shut down happens sometimes (starts but dies 2 seconds later)

Heated seats do not work

Dome lights do not turn on when opening the door

Radio lights on with the ignition off (they were the only lights on in the truck)

Turning on the parking or headlights does not immediately turn on instrument lights (there is a 5-20 second delay)

Window switches may or may not be lit

Truck starts and runs fine (when it is not shut down by security system)

abadv8 · April 13, 2014

I was just checking out everything in the engine compartment and found a chaffed wire on the ECM plug. It looked like the two harnesses to the ECM were rubbing together. I didn't see anything that would have been making contact. So, I just wrapped it in tape and moved on to the next set of connectors.

I wound up unplugging and reseating all of the major underhood connectors (ECM, PCM/TCM, and engine harness). They all looked good, with the exception of the top plug on the engine. That one had a few wires that were nibbled on, but not shorting. I think I'll probably liquid tape those just to seal them up.

After I disconnected and reseated everything, I tried starting the truck. It started, ran, and everything worked. I only let it run for 10 minutes, but everything was good. However, after 3 or 4 minutes the security light lit up. I'm not sure what that's telling me, but when I shut it off and tried to restart, it still worked.

I've never seen the security light before Monday.

Next up I tried to pull the B and U codes. No dice. I still get a communication failure. Although, I can now pull and reset the P codes. I had two history codes for glow plugs (I replaced three in December), and a P0650 (that I no doubt set when I was messing with the IPC.

I'm still at a loss here...

8.1HD/ALLISON · April 13, 2014

Sounds like lots of wiring problems. The underhood fuse block is one place mice love to get into. If you haven't checked underside of that fuse panel I would check there next.

Sent from my LGL86C using Tapatalk