Troubleshooting Trailer Brakes Engaging Without a Vehicle Trailer Brake Controller Installed

Question:

My brakes on my trailer come on when I push on the brakes of my truck that dose not have an electric brake controller on it. What can I do

asked by: Danny C

Expert Reply:

It sounds like your trailer connection is really needing some cleaning or your trailer has a brake controller integrated. Start by cleaning your 7-way trailer connector on your truck and trailer plug using some sand paper or steel wool to mitigate any power jump from one pin to another. Then use dielectric grease # 11755 to keep water and debris out of the connection and test your system again.

If that tests correctly then you have a short on your trailer side of the wiring or there is a brake controller of some sort on your trailer. Your brake assemblies wouldn't be getting any signal if one of these two options weren't in place. If your brake lights were connected to your trailer without any controller and it is a short, you will also get intermittent power at your brake magnets when the turn signal activates. You can use a circuit tester like # PTW2993 to test that function. If you are getting power at your brake magnets for both these functions, then I recommend running new wires to your brake assemblies using # 10-1-1 wire and then 7-Way Molded Trailer Plug with Junction Box # HS381-9000. This will help you isolate that circuit and give you a clean connection point for testing or troubleshooting in the future. You will want ring terminals # 44-5310A and butt connectors # DW05745-5.