Trailer Grounding Issue 2006 Silverado

[NotSure]

New here, first post.

 

I'm having an issue with my trailer lights not working. The brakes work and the breakaway battery charges, no lights though. Tested the the trailer lights at the trailer plug with a 12 volt power source and they worked. I have no ground on the truck side when measured with a meter (not sure how the brakes work).

 

At the truck, I put an analog meter (positive lead to the +12) and (negative lead to the Left or Right tail lights) and got 12 volts with the hazards on.

 

Everything worked last year, but I pulled three other trailers between then and now. I think it is a fuse issue, but I can't figure out which fuses are tied to the trailer light operation. I found 3 fuses I could tie to the trailer by the abbreviation TRL, and 2 were blown. I replaced those and still no lights. Any ideas? Are there any other fuses tied to the trailer? Thanks in advance for any advice.

[Cap'n Hook]

If the rear connector on the truck is working properly when you check with a test light, that would eliminate the truck and it's fuse from problems. Next, check if the trailer has a battery backup for brakes (if it has electric brakes ALL trailers will have a battery backup), make sure the battery is good. There should be a small box attached to the trailer somewhere inline with the trailer wiring to this box. There may also be a fuse protecting the battery in the box. Also, if the trailer ground wires are loose at any connection, you may also be losing continuity some where on the ground side. It's as simple as tracing the wires and checking the connections are tight. Last place to look, if the trailer has electric brakes, there may be a shorted wire inside the wheel hub requiring removal. If you don't feel confident in tackling the job take it to a competent trailer shop.

 

Edit: Forgot to mention, if you've never had this particular trailer hooked up to your truck's trailer connector, it's possible the trailer's (or your truck's) connector isn't wired the same (matched).

Edited December 9, 2016 by Cap'n Hook