vinny

I would like to thank everyone for your input and helping me solve this problem. You guys are great , Thanks again

You are the winner, It was the trolley valve. My brother thinks he may have leaned on it when he put the dash back together. Thank You so much, It was driving me crazy.

I had the trailer hooked up and put new plug which was the same and every worked fine until the next day. even checked it with another trailer and it worked fine. I will check if something is crossed. Thank You

Thank You Chuck, I will check that out

I disconnected the wires from the switch thinking it was a bad switch but even when disconnected the cold side has power all the time causing the lights to stay on. I also disconnected brake controller with no luck. I will check the trolley valve and foot brake treadle. Thank You

hello, can anyone help. I have a 1983 mack r model 685. I installed an electric trailer brake unit yesterday, everything worked fine untill today.the lights are staying on all the time. I traced the problem back to the brake light switch wiring. For some strange reason now the cold side of swich has power all the time and the hot side is dead even with the wiring disconnected from the switch. what would cause that? I disconnected the trailer brake unit still no luck. A wiring diagram would be helpfull to trace back the wires. Thanks