Twice now I have had the harness fry on me. Both times i noticed when the running lights were on, switch off. The plug receiver itself is corroding and shorting itself, backfeeding the running lights.

Where am I going wrong. I have a drawtite "activator" controller which has been acting odd also. the light on it is on sometimes when im not even touching the brakes. indicating its sending a signal to the brake wire.

For the life of me I cannot figure it out, and its getting tougher and tougher to find my way through all the wiring anyhow.

Am I best off just getting a new controller and wiring and starting from scratch?

 

On most controllers, there should be a light "on", that indicates that the trailer is connected and brakes are connected, it will change color when brakes are pressed. Does your truck have factory trailer/tow harness? Check for frays where it rubs frame rail, in the area where you spare tire is near frame on drivers side.
Ive found that 90% of the time, the problem with trailer/truck wiring is in the plugs, replace both trailer and truck plugs and try it again.

 

see if you can find a tube of dielectric grease and especially the truck plug needs it and then wrap the back with rubber tape and then electrical tape

 

ive done both things, dialectric in the plug, and checked for bad wires and shorts. when crawling under a truck with 175000 on it, im thinking time would be better spent putting in a new controller and harness wiring.

 

I would tend to agree with you, but before you go thru all that, make sure that the trailer plugs, both on the truck and trailer, are receiving a good ground. Bad grounds cause more problems than any amount of time and money can cure!

chaikwa.