Taillight ground issue?

[MMeier]

On the '93 the past few months my brake controller would wig out after going through the self serve wash. Few nights back I wanted to use it to move one of my small trailers around... turn on lights and the trailer lights would be very dim, and the brakes were trying to apply. Thinking the original plug has been on their since '93 I replaced it today... still have very dim trailer lights and the controller is not doing its thing. Where the original plug was wired in was with one of those adapters that ties in at the factory connection on left frame rail, put a tset light to verify what everything was before I redid it, off the white ( one of 3) wire there was a wire t tapped off to a ground point on the bumper, does this sound right? want some opinions before I go back in there tomorrow, I thought it should be grounded already with out that one wire??? Oh, plug it into the '03 , everything works just fine.

 

[PToombs]

Mark, if that white wire is between the "T" tap and the trailer plug, it should be a ground wire. I looked in the FSM and didn't see a white wire in the factory wiring. The factory trailer harness has a white wire, same as the aftermarket wires. The factory wiring has a ground in it. I couldn't find it in the FSM, but it's on the frame back there. I just can't remember where I saw it.

Those "T" taps rot out internally too. I saw one on a chevy that the lites were acting funny, and all the connections looked good. I pulled the "T" tap, and the lights worked normal. I cut it open, and it was all corrosion inside, which shorted between the terminals.

 

[cerberusiam]

IIRC, the solid black wire in the wiring harness is vehicle ground. Its the only other wire left after finding all the other light function wires. I wired my trailer plug that way and with a good trailer ground wire everything works correctly, even the brakes. I also considered grounding it to the frame but the amount corrosion and water there caused some hesitation so used the harness ground and sealed it as well as possible.



T-taps and scotch locks are problematic especially at the back of a truck. Like Pete, said I have to pull them out and redo them due to corrosion and shorting.

 

[MMeier]

Dinked around with it some today... 70* out... and almost think that the rust and crap inside the reciever tube was most of the problem, cleaned that up and it seems to work pretty good. Found this by having the trailer hooked up and starting pushing the insert around and the lights began to do what they are supposed to, also, ran a temporary ground wire between trailer frame and truck and that worked also. Never had this problem before. I was wondering about that t connector being as old as the truck, might replace that too to be on the safe side. Thanks for the responses guys!!