Troubleshooting Malfunctioning Trailer Lamps on 2015 Lakota Horse trailer

Updated 09/16/2015 | Published 09/14/2015

Question:

I have a 6 month old horse trailer and the two lights on the left rear of the trailer are now functioning odly. When all of the lights are off on the trailer, the left turn signals will only blink on the 4 bulbs in the center of the fixture. The same lights on the right are blinking with all 10 bulbs and are fine. When all of the lights on the trailer are on, these turn signals will not blink at all. This just seems very odd. Any ideas on what wiring to check?

asked by: Cindy I

Expert Reply:

It sounds as if you might have two issues going on. When the turn signals are activated, all the diodes in the LED lamp should blink. If they don't (assuming that particular lamp was wired correctly), the lamp is faulty and should be replaced.

For the issue with the turn signals not functioning when the running lights are switched on, that sounds like a ground issue. When you turn on the vehicle headlights, the trailer wiring system is drawing maximum amperage. If there's a ground problem, that's when it'll show up. Check the main ground connection on the trailer, coming off the trailer connector. The ground wire should be securely fastened to the trailer tongue or frame. Make sure the ground connection is tight, and not corroded. Each trailer lamp will get its ground connection either from its mounting hardware being connected to the trailer frame, or via a separate ground wire. Make sure this connection is also secure and not corroded.

I'll link you to some FAQ articles about trailer wiring. One is an overview, the other provides some troubleshooting strategies.

expert reply by: Mike L