Troubleshooting No Trailer Lights on Right Side of Trailer with New 7-Way

Question:

I recently purchased a 7 pin trailer connector to replace the factory 4 pin on my 2000 ford f-250 Super Duty. The install went well, however, I have no right turn signal or brake light on the passenger side of my trailer. All the lights seem to work just fine on the truck and the trailer lights work fine on my other truck. Ive checked all the fuses, made sure my plug was all the way pushed in, checked to ensure the 2 included relays went in the correct locations and Im still getting nothing out of the right side. any thoughts?

asked by: Andrew P

Expert Reply:

Since the trailer lights work perfectly when connected to a different truck, the issue certainly appears to be somewhere on your 2000 Ford F-250. You did mention that you checked the fuses in your truck, but I recommend verifying that the 7.5A mini fuse located in the number 3 position (inside the power distribution box in the engine compartment) is present and in good condition. This is the particular fuse on your F-250 that is for the trailer right stop/turn lamp.

If that fuse is okay, then I recommend testing the 7-Way on the truck with circuit tester like # PTW2993. Test the right turn/stop circuit pin (3 o'clock position) with that function activated on the truck. If you don't get power there, also test the wire just behind the connector that is going to that pin for power. If you receive power there, then the connector itself is bad and will need to be replaced.

Otherwise, I simply recommend inspecting the wiring back from the connector for any damaged or exposed areas that need to be replaced. You can try testing the wire every so often to see if you can find where the voltage drop starts.

expert reply by: Chris R