Troubleshooting 6-Way to 7-Way Trailer Adapter Where Functions Arent Working Correctly

Updated 10/15/2018 | Published 10/13/2018

Products Featured in This Question

Hopkins Heavy-Duty, Coiled Trailer Connector Adapter - 7-Way to 6-Pole Round - Center Pin 12V Power

(30)

$57.88

Adapter 6-Pole to 7-Pole Trailer Wiring Adapter

(126)

$23.69

Hook Probe Circuit Tester

(60)

$12.27

Question:

Have a 95 GMC with 6 round and just bought a trailer with 7 Blade, got an adapter #47435 and nothing works. If I put the running lights on in my truck then they come on but no turn signal or brakes.

asked by: Brandon

Expert Reply:

It is very likely that your 6-way is not wired for the 6-Pole to 7-Pole Trailer Wiring Adapter # 47435. Trailer wiring with 6-way connectors can have two ways the brake and hot are wired, so it is likely the 12V hot and brake output wires are not in the correct locations, which is easy to switch. This adapter is made for the 12v power to be the center pin of your 6-way and the pin in the 10 o'clock position for the brakes. You can verify this using a circuit tester like part # PTW2993.

Because some of the features work when you turn your running lights on, it is likely there is a ground issue on your trailer. Make sure the ground connection near your coupler and the ground connections at your tail lights and electric brakes are all bare metal to metal and free of corrosion or debris. Tail lights are often grounded through the mounting hardware, so you will want to make sure those connections are bare metal as well.

I've attached an article on trailer wiring to help with trailer connector pin function as well as other helps.

expert reply by: Jason S