Troubleshooting Right Turn Signal Not Working On Trailer With Wishbone Harness

Question:

Hello there! I have a 4 pin plug with five wires coming out of my old 1977 Scamp 13 trailer and its hooked into my 4 pin plug with 4 wires in my 2017 RAV4 tow vehicle. Brake lights running lights, and left turn signal on the trailer work perfectly, but when I hit my right turn signal all the lights flash in hazard mode. I am thinking of buying a new 4 pin plug with five wires for my trailer as its very old. But, am I going down the wrong road? I hope this description below is helpful... I do truly appreciate your time and consideration! The RAV4s tow vehicle new connector is set up as follows... 1 green/black wire female connector 2 yellow/black wire female connector 3 brown/black wire female connector 4 white/black wire male connector The trailers old connector is set up as follows... 1 green wire male connector 2 yellow wire male connector 3 green/brown wire and yellow/brown 2 wires male connector 4 white wire female connector

asked by: Guy B

Expert Reply:

It looks like you have a traditional 4-way connector on your Toyota RAV4 and wishbone style connector like part # A35W42B on your trailer that allows you to run separate tail lights back to each side of your trailer. You can replace the wish bone trailer connector on your trailer with A35W42B but that may not solve your wiring issues without knowing for sure where the problem is.

First you want to make sure all of your ground connections on the RAV4 and the trailer connector are attached to a clean bare metal surface. Then check to make sure all of the connections behind the tail lights are properly seated.

If your grounds and connections are okay then you want to get a circuit tester like part # PTW2993 and have someone activate the right turn signal while you check the circuit for power, it is normally the green wire on the vehicle connector. If the right turn signal circuit doesn't show power, then it needs to be replaced with part # 118578 for the 2017 Toyota RAV4.

If you have power at the right turn circuit of the vehicle connector then you know the issue is on the trailer side wiring. You want to trace the passenger side stop/turn wire back on your trailer connector looking for any damage or frayed wires. You also want to make sure the trailer side connector has a good connection with the vehicle connector. From your photo it does look like you have some damage on the wires, so if it turns out to be the trailer side wiring, I recommend replacing your trailer connector with 35 Ft 4-Way Trailer Wiring Harness part # A35W42B. This wish bone style wiring harness will give you the same setup you already have.