What To Do When Trailer Brakes Stop Working After Replacing a 7 Way Plug

Question:

Changed my 7 way and checked and replaced fuses but my trailer breaks are not working. They were working before I changed the 7way. Also my breaking control system inside the truck is not lighting up

asked by: Lee

Expert Reply:

If your brake controller is not lighting up, this is most likely the cause for your trailer brakes not working. Typically this will mean that there is either no power going to the controller or the controller has gone bad and will need to be replaced. With that being said, I highly suggest checking all your ground connections, both on the trailer and vehicle, as even one that has gone bad can cause any number of issues.

If all the grounds look good, you will need to test the black power wire going to the brake controller. This should have constant power. If there is power going to the controller and it is still not turning on, then it will need to be replaced.

However, if there is no power going to it, you will need to check a few things. First, if this is an aftermarket set up that did not have a port under the dash for the brake controller, you will need to check all the wiring and circuit breakers as you either have a short or the circuit breaker tripped and will need to be replaced.

If you do have the factory port for a brake controller, you will need to recheck your towing fuses. If all of them look good, you will most likely need to take the vehicle to an auto shop to have it diagnosed and repaired.

If none of this gets you back up and running properly, let me know and we can try something else.

expert reply by: Lazer S