swordfish

First the stats...2001 2500 QC LB 5 spd stock. Brake-force brake controller wired into the factory harness next to clutch below fuse box. Since bought the controller LED was continuously on. 2 7 pin connections in the back...one in the bed, one by the receiver hitch. I was pulling a 28 foot gooseneck featherlite enclosed trailer with a 6 pin connector.

Last night I had the trailer hooked up and everything was working fine as the way it should be. I got to my destination, loaded up the car I was picking up. I went to get in my truck and noticed the running lights on the trailer were out, lights on the truck were still on. I messed with the connection thinking that might be it. I got nothing. I got in the truck and noticed the LED on the brake controller was out. I stepped on the brakes and the LED on the controller came on as well as all the trailer lights. Let off the brake and the running lights went out. If I apply the turn signals...those work either way. I disconnected the brake controller to see if that would help and got the same result running lights on with only brake pressed.

Next we took a test light to the back of the truck. We tested the harness in the bed and the one by the receiver. Using the test light we determined that the trailer lights and everything were doing exactly what the truck told it to do....meaning the signal to the back of the truck was the same...turn signals worked, running lights only worked when brake was pressed.

I am no electrical genius so I am kinda scratching my head on this one. Maybe someone out there with a little more experience could maybe give me some insight on what to check. I appreciate any help given.

Swordfish

waam

Try a new ground wire. I had that once on a travel trailer, lights did all kind of weird things. I talked to a lot of people about my lights doing weird things. Head maintenance man in our shop told me that I lost my ground, he told me then to attach a new wire from the body of my truck to the frame. I did that and my problem was taken care of. Maybe it will help. waam Holland, Mich.

SRTchris

i had an old POS 70 roadrunner that suffered from " funky disco light syndrome" too, talked to my mechanic buddy and thats what he said to do as well, changed and put new grounds and voi-la!!! no more issues!! i always try that first ( and check bulbs ) before trying to find a gremlim that isn't there.

swordfish

Is there a particular ground I should be looking for?

Bonshawman

I concur - it is a ground problem (or another "bad" connection somehwere, so cross-feeding is taking place). My backup lights on my headache rack on my RAM stopped working, and two of my side body marker lights came on in reverse ! I traced wires - all OK (obviously, was working correctly before the problem). Ground and wiring in the back was shoddy - re-did connections and all restored to normal.

SRTchris

put em every where, bed to frame, cab to frame, replace the connectors on your trailer too ( the ground ) and if your wife get motion sickness like mine maybe even help with static charge build up too.

waam

Just some kind of bump, I'm told, and you can lose your ground. On my old truck I put a new ground wire from the tail light screw to the body and then to frame. That was when tail lights where real glass with metal frames and the gas tank was still behind the seat. waam Holland, Mich.