Troubleshooting Only One Light Showing On Hopkins 7-Way RV Style Trailer Connector

Question:

Only one of my adapter lights come on the first one to the left none of my trailer lights work what can be the problem

asked by: Louie S

Expert Reply:

Based on the LED position you described on the # HM48503 it sounds like you're facing the trailer and the 12V power light is lit up. If you are facing the rear of your vehicle that would be the running lights. I would go ahead and verify this using a circuit tester like the # PTW2993. Check all of the pins on your 7-way to make sure it is the 7-way on your vehicle and not the test lights on the connector malfunctioning.

Assuming you don't have power when you test your turn signals and brake lights you know the problem is on the vehicle side. Start by making sure the connector is clean and not damaged. If this checks out I would double check the wires directly behind the connector to rule out the 7-way connector itself.

Depending on the wiring harness you have installed, or if this is a factory 7-way, I would also be checking fuses to make sure they aren't blown. If you have an aftermarket 4-way with a 7-way adapter I would check the wires running into and out of the converter box. If you have power running in but not out it is a bad converter and you will need to replace the wiring harness.

expert reply by: Robin H