Troubleshooting Left Side Tail Lights Not Working on Trailer

Question:

I have a 7 prong trailer. All the lights work execpt the left side tail light doesnt have any power at all no brake no blinker nothing. All marker lights work and the right brake and blinker work. Why wont the left work ?

asked by: Michael

Expert Reply:

If just the left side tail lights on your trailer are not working, there is likely an issue somewhere along the wiring on that side of the trailer.

I first recommend checking the trailer side 7-Way connector for any built up debris or corrosion inside the pins, simply cleaning as needed. If the connector looks okay, check along the trailer wiring on the left side and look for any pinched, frayed, or damaged wiring and replace if needed. Also make sure that the ground wires on the trailer are attached to a clean, bare metal surface that is free of any dirt or corrosion. Inspect the wires going into the lights in question for any kinks or pinches.

Also check to make sure that there are no missing or damaged fuses related to trailer towing on your vehicle. You can check your copy of the owner's manual for the relevant fuse locations.

If you are still unable to resolve the issue, please let me know and I will be happy to look into this further.

expert reply by: Chris R