Troubleshooting a 4-Way Wishbone Trailer Connector Without Running Lights

Question:

I have a 4 way on my trailer w/ 5 wires and im plugging into a 4 way w/ 4 wires. I have brake lights and turn signals but cannot get the running lights to work. My running light are on the brown wire should they be on a different wire ?

asked by: Jim K

Expert Reply:

Traditionally, the brown wire is the running lights. On your trailer you have a 4-way wishbone connector, similar to our part # A35W42B. With a wishbone the running light circuit is ran on two wires one going to each side of the trailer. This usually makes wiring the trailer easier.

Do you have running lights at the vehicle's connector? Use a circuit tester, like part # PTW2992, to test each function on the back of your tow vehicle. This will isolate whether the problem is with the vehicle or the trailer. If it's on the vehicle side, then check fuses and make sure the connector is clean and free of any corrosion. If these are good, then you'll need to follow the wire through the vehicle looking for any damage.

If everything is fine at the vehicle's connector, then inspect the trailer's connector for any debris or corrosion. Then follow the two wires that go to the running lights looking for any damage or pinches.

If you still can't find the issue let me know and we'll keep troubleshooting.

expert reply by: Charles S