Weirdest tail light ever

[J.d.lct]

Everything worked well until I started my 2007 gmc Sierra 2500hd to leave work. Service tpms message showed up. Looked at the tpms and it couldn't read left rear tire pressure. Made a left turn, blinker started to blink fast after a few seconds. Then my cruise control wouldn't set and I got pulled over for no left rear lights and white lights showing on rear of vehicle. I got home and did some checking. No left rear tire tpms reading, no cruise control, no left rear blinker, running, or brake lights, but left and right reverse lights are on all the time....except when its in reverse, then the reverse lights shut off... Really need a hand here guys, thanks.

[Josh_perry24]

All of those components should be controlled by the body control module. Any water damage or reasons you could see something being wrong with the BCM?

[Jsdirt]

Sounds like a grounding issue.

 

Things like lights turning on when they shouldn't, or on the opposite side intended, or on a completely different circuit from the one your activating, will happen due to a lack of a good ground, or a weak short to ground. Even crossed filaments from a burnout in dual-filament bulbs, like the 1157 (or 3047 on these new ones), will do that in rare instances.

 

But then with a BCM involved, it could be that magic box itself.

[J.d.lct]

Bcm should be good....after that problem with my 2013 I sealed it off with over sized shrink wrap and sealed it off.....I'll cut it off and look though. Thanks.

[Doug_Scott]

Jsdirt has the right direction to follow. Take a good look at each and every light socket in the parking light, backup lights, and brake/signal circuits. Either take one bulb out of the circuits at a time, or take them all out, and add back in one at a time. This should show you which socket bulb is at fault. Grounds are very important as well.

[Graphic]

Might also check the trailer wiring connector if you have one. Make sure nothing conductive is in there, water, plug piece, etc.

 

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