Trailer Left Turn/Brake and Running Lamps Not Functioning on 2009 Chevy Silverado

Question:

All of my lights worked in the fall when I put the trailer away get it out this year and only the right turn/brake work now. I assumed it was the trailer and everything on the trailer works while hooked to other vehicles. Check power at 7 way at rear of truck and the right turn/brake is the only location with power. Check all fuses under the hood and they were all good. Is there more fuses someplace else for this? Wiring harness and plugs at rear of truck are all clean and corrosion free.

asked by: Matt

Expert Reply:

I'm not inclined to think the problem you're having is caused by a blown fuse, since the right turn/brake, left turn/brake and trailer running light circuits are all fused separately. It's fairly unlikely for two of the three to be blown, but it's worth checking a second time. The trailer right turn/brake is the fuse in position # 3, left turn/brake in # 10 and running lamps in # 25.

Next, unplug the vehicle wiring harness from the rear of your 7-way (see photo). There will be a gray locking clip that needs to be slid away from the bumper before the plug can be removed. Use a circuit tester on the pins of the wiring harness as each function is activated. If you get signal for the left turn/brake and running lamps, you have proven that the 7-way plug itself is faulty and should be replaced. We offer a replacement, part # PK11916.

If you don't find power for those circuits on that harness, then there is a problem of some kind with the tow package on the vehicle that we can look into further. Please get back with me, and let me know what you find.

expert reply by: Mike L