Troublehsooting Trailer Lights that Only Turn Signals Work Intermittently

Question:

Hi. I just picked up a 2001 Coleman Santa Fe. When i plugged in to the 7 pin connector with my truck I only had the LH side brake light and blinker working. I dragged it the short distance to my home like this as the trailer side of the 7 pin connector had some corrosion on it from sitting and I figured could just swap out the trailer side connector. This trailer sat for many many years before I picked it up. Upon removal of the trailer side 7 pin connector I noticed that there was no wire in the middle location. I removed the 6 wires around the outside and then put them into a new connector. When I plugged it in, the only thing that lit up was the LH and RH blinkers and even this was occasional. i was careful to ensure the wires were placed in the same position as in the old connector. 1 Does the fact that I have no wire for the middle location on the 7 pin connector mess everything else up? 2 Does this seem like a bad ground wire and I should start by tracing it to its origin? 3 Any other ideas as I try and chase this issue down? Thanks

asked by: Dan C

Expert Reply:

Not having a circuit on the middle pin will not harm anything. It's normally for reverse lights and I'm guessing the trailer doesn't have any.

A loose or weak ground is likely your problem. Since the trailer has been sitting for so long, and there was corrosion in the connector, there's a very good chance you'll find more. I would start by checking the grounds for each light and make sure their going to a good, clean, metal surface. Inspect the mounting studs if the lights ground through them, they need to be clean as well.

If thre aren't any issues with the grounds then you will want to inspect all of the wiring for any damage or exposed wires. If after this you still are having the same issue, let me know and we'll continue to troubleshoot your trailer.

expert reply by: Charles S