Troubleshooting Trailer Running Lights Not Functioning on Trailer

Question:

I hope you can help, When I bought my boat the trailer had a 5 wire blue wire included flat tail. Not sure why it simply did not come with a 4 wire set up. The trailer doesnt have breaks or auxiliary lights. I change the wire set up on the trailer to a 4 flat because I had an incident where the wires were pulled out on one side. since I changed to the four flat set up I added the C E Smith lights that go on pvc.pipes. As directed hook each side to the brown wire and I took the ground and grounded it to the screw that holds the tail lights to the trailer. For some reason i cant get them to come on. my blinkers will work but nothing happens with running lights. brake lights work blinkers work but nothing else what am I missing?? Should i try and ground direct to the trailer or go back to the 5 wire set up. If so why?? Thank you

asked by: Jay

Expert Reply:

First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # PTW2993 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached.

If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. My guess would be you are overdrawing the running light circuit now and they won't come on. This could also be true if the running light circuit is dead on the 4-way as you test it as it would indicate a blown fuse.

expert reply by: Jameson C