I Have a 2006 Dodge Ram 2500 and my reverse lights work when I go in reverse but when I turn my headlights on or Park lamps my reverse lights turn on. I looked in the electrical schematics and and do not see a common power for the taillamps and reverse lamp. Except for the unit the lamps are plugged into..I tried other ones and still same problem. The only thing I can think of is a wire is touching somewhere. Any suggestions?

 

The only thing you can really do is what you suggest------start looking at the wiring

 

Yep, short in the wiring or bad socket. I would pull both tail light circuit boards from the housing and disconnect one side and see if it still does it and go from there

 

This is the first place you should start.... those boards go bad from time to time.

Next thing to check is the multifunction switch, and then dig into the wiring, which is the hard part...

 

I did try the socket thing with no luck both do it and I tried a buddies taillights and the same thing. I think it is in the TIPM. The nice thing is the dealer that just sold me the used truck is going to look at it free of charge and hopefully find the problem. I will let you all know what they find.

 

Gremlins like that in a 2006 would point directly to the TIPM. I highly doubt you have a harness issue.