Trailer light woes

[MMcKenzie]

My 2006 3500 has two trailer light connectors. One is the 7 pin in the bumper and the other is a four way flat connecter under the bumper bundled to the hitch. I noticed yesterday that my lights had quit working. I always use the 7 pin hookup with a 5 pin adapter so I can run the trailer brakes on my boat trailer. I unhooked that and hooked it up to the four pin connection and everything worked fine.



Basically, the 7 pin has quit working but the four pin still works. What would cause this and how do I fix it. Has anyone had a similar problem? I checked the fuses and everything seems fine.

 

[jelag]

I've had problems with the 7 pin connector on each of my trucks... . I've had to take it apart and replace the connector at the rear of the wiring harness with butt connectors and shrink tube with sealant in it... the chemicals on the road here seem to get into the connector give problems... . its the only connector on the truck we've had problems with...

To make it easier to connect our trailers, we've added an additional 7 pin connector to the inside of the bed at the rear on the drivers side... . at the same time we are removing and pitching the connector into the wiring harness we are adding additional wires going to the new plug...

Because every thing we own has the 7 pin connector we also remove the 4 pin connector...

 

[MMcKenzie]

Thanks for the info.



I have also heard about owners having similar problems and having something reset at the dealer in the computer. Any info on this?

 

[B.G. Smith]

Thanks for the info.



I have also heard about owners having similar problems and having something reset at the dealer in the computer. Any info on this?

That would be the TIPM, Totally Integrated Power Module. When it trips from overload or short circuit it has to be reset by dealer and I have heard that the reset can only be done two times then it has to be replaced. I don't think your lights would work on the 4-pin connecter if the TIPM were the problem. bg

 

[MMeier]

Did you check the fuse?

 

[PBrauer]

Thanks for the info.



I have also heard about owners having similar problems and having something reset at the dealer in the computer. Any info on this?

If one connector works but not the other then I wouldn't worry about the TIPM. The most likely problem is your adapter. Check continuity through it with a meter. There is a diagram printed/molded into the plug cover (7) at the bumper.



After that I'd check the grounds. All of the "power" wires should be splices but the grounds might be separate wires to the body/frame. Don't forget that one path for ground is from the ball to the tongue. Lift the trailer off the ball to isolate the plug. Measure resistance between the truck and trailer frame using each connector. Then measure again while "hitched".



The "conditon" you've read about involving the TIPM, if it's the one I'm thinking about, involves the turn signals and as far as I can tell doesn't happen to '06 trucks... or at least it's not as likely. Your problem is probably something fairly simple. My money's on the adapter.

 

[JHardwick]

My guess would be the 4-flat/7 pin RV adapter. Just buy a 7 pin RV and wire your boat trailer with that and skip those junk adapters.

 

[MMcKenzie]

Thanks for the advise and help. I was hoping it did not have something to do with the computer.



I will have more time to work on it this weekend and see if I can't find the problem and I will report back.

 

[RJWEST]

On the 02 the flat connector running lights comes from the same circuit as the
truck lights,
The 7 pin, running lights has a seperete relay and fuse...

Don'e know if that helps any, My guess, you also have a seperate circuit for the 7 pin.