Troubleshooting No Brake or Turn Signals on Trailer with 4-Way Connector  

Question:

Expert Reply:

There are a few possible reasons as to why you aren't getting the brake/turn signals to work on your trailer. The first thing I recommend doing if you haven't already is testing the tow vehicle's 4-Way with a circuit tester like # PTW2979 to help narrow down where the problem area could be.

Test the turn/brake circuit pins on the 4-Way while you have those functions activated on the vehicle. If you get appropriate power then you know the issue is somewhere on the trailer. If you don't get power then the problem is on the tow vehicle.

If you got power when testing the 4-Way I recommend visually inspecting the trailer's 4-Way for any debris or corrosion that might be built up inside the pins, cleaning out as needed. Then check to make sure the main harness ground is securely attached to a clean, bare metal surface that's free of any debris or corrosion. Do the same for the light assemblies themselves, whether they use a dedicated wire or simply ground through their mounting hardware.

If you didn't get power when testing the tow vehicle's 4-Way the most common culprit would be a blown fuse under the hood. Check your owner's manual for any fuse locations related to trailer lights and replace as needed. You might also test the wiring directly behind the connector for power as well. If you get power on the wires then the 4-Way connector itself just needs to be replaced.

Let me know what you find if this doesn't resolve the issue and we can go from there!

expert reply by: Chris R

0