Troubleshooting Trailer Brake Controller Installation in Ford-Based RV

Question:

The c nor the numbers light up. also when you turn on head lights the trailer brakes come on, all lights work on trailer. Ford running gear on class a RV. hooked up under dash just plug in.

asked by: Al H

Expert Reply:

It sounds like you are troubleshooting a trailer brake controller installation in your Ford based RV.

All trailer brake controllers share the same 4-wire hookup. The BLACK wire takes in 12V operating power from the vehicle battery; the WHITE wire is for battery ground; the RED wire takes in the triggering signal from the cold side of the brake light switch; and the BLUE wire carries the controller output to the trailer connector.

If your trailer brakes are engaging when you turn the RV lights on then your wiring adapter, which plugs in under the dash, is the incorrect one or it is mis-wired. If the controller does not appear to have power (if it does not light up at all) then that issue is on the BLACK 12V power wire or another part of that circuit.

For more help you can refer to the two linked articles on brake controller installation and troubleshooting.

expert reply by: Adam R