Trailer Brakes Not Working Using a Homemade 7 Way Adapter

Question:

I am borrowing my neighbors horse trailer which has a 7 way round pin plug and my vehicle has a 6 way round pin plug. Since no adapters could be found for this application, a friend wired up an adapter. The blue wire on the 7 way is in the center pin and the blue wire on the 6 way is on the brake pin. When hooked up all lights on the trailer worktail lites, clearance, brake lites, turn signals but when using the manual control on the brake controller, the trailer brakes do not engage. The numbers on the brake controller light up so it acts like everything is right any ideas? Thanks for your help.

asked by: Ed B

Expert Reply:

The first thing I would do is check the power back to the vehicle side by using a circuit tester like # PTW2993. Then apply the manual override on the brake controller. If there is no power getting back to the vehicle side connector, then there is a break somewhere between the controller and the trailer connector.

Secondly, check to make sure the adapter is wired correctly. Then plug the adapter into the vehicle 6-way round pin connector and test the output side of the adapter using a circuit tester. If there is no power at the output side of the adapter, then the issue is with the adapter.

Check the wires on the trailer brake magnets. Each magnet should have two wires: one for power, and one for ground. Make sure that the ground wire is attached to a clean metal area without any paint or corrosion. The power wire should be intact and have a solid connection to the electric brake signal wire. It does not matter which wire does what, just that one wire is powered and the other is grounded.

I included a few FAQ's for you to look at too.

expert reply by: Chris B