Troubleshooting Stop and Turn Signals Not Working for Trailer

Question:

I have a 08 F250 with trailer wiring problems. I have running lights on the trailer but nothing else. The brake assist works sporadically, mostly with weight in the trailer. Seems to be getting worse, ie less sporadic. Checked the fuses and relays and they seem good. I was going to replace the white ground but noticed there’s 3 smaller ground wires black with white stripes that seem factory spliced into the one white 10 ga ground wire that runs to stock connector close to bumper. Can I still cut white wire below the splice and use butt end connections or will this make problems worse. I can’t see much more upstream with the three smaller grounds and where they go Any help is appreciated.

asked by: Bill H

Expert Reply:

The ground connection is an excellent place to start troubleshooting any wiring problems you may be having. You can definitely use butt connectors to splice in a new ground connection but I recommend using heat shrink butt connectors like the Deka # DW05745-5 because it gives better protection than just standard butt connectors.

If that doesn't fix the issue then the next step is to check your trailer and vehicle connection points as well as the wiring for your trailer lights. You can narrow down the issue to your trailer or truck by either hooking your trailer up to a different vehicle, or using a circuit tester to check the pins on your F-250.

I'm attaching a helpful article for trailer wiring troubleshooting for you to check out as well.

expert reply by: Jon G