Troubleshooting Right Turn Signal Not Working on Trailer Taillights

Updated 05/23/2024 | Published 05/15/2010

Products Featured in This Question

Peterson Combination Trailer Tail Light - 6 Function - Incandescent - Square - Passenger Side

(872)

$5.17

Hook Probe Circuit Tester

(60)

$12.27

Question:

I noticed my passenger side directional not working, bulb looked good, but replaced it anyway, still no good. I looked further and it seems as though the middle lead looks broken at the bottom where I guess it would return to ground for the directional. The side markers work, brake light works and it lights when the lights are on just no directional. My question is, is this lead supposed to be seperated on the right light because it isnt on the left and should I just purchase the replacement right tail light 432200?

asked by: Peter M

Expert Reply:

First, disconnect the trailer from the tow vehicle so you can check the vehicle side connector. Using a circuit tester like part # PTW2993, test the functions of the connector; specifically check the right turn/brake, to make sure the signal is making it to the connector. If it is not working at the connector, there might be a fuse blown or missing in the power distribution box under the hood. Also, make sure both connectors are clean, and free of any dirt or corrosion.

This very well could be a ground problem. If so, correcting the bad ground or broken wire could solve the problem. If it is a wiring problem, and not a hardware problem, replacing the whole light will not help as the malfunction is in the wiring. Sometimes, trailer lights ground through the mounting studs. Make sure the connection point is free of rust and corrosion as that could cause a bad ground.

The driver side light should have a yellow and brown wire connected. The yellow wire goes in the right hole if looking at the back of the driver side light. Brown goes in the left hole (the lights are marked). The brown wire is the running lights. The yellow wire is left turn and brake light.

The passenger side light should have a green and brown wire connected. The brown wire is the running lights. The green wire is right turn and brake light.

I am including a link to a FAQ page on trailer wiring which will describe how to troubleshoot your trailer wiring.

expert reply by: Michael H

Ron

6/9/2020

Getting no power on green wire from f150 to trailer hookup. Everything else works on right side except turn signal. Wire doesn’t seem to be broken in harness. It is a 4 pin hook up

Chris R.

6/12/2020

If you aren't getting any power on that circuit I'm thinking there's a blown fuse under the hood. In your copy of the owner's manual the fuse locations will be listed. Look for the one that's in charge of the trailer right turn/brake light circuit and check to make sure it's in good condition - replacing if needed.

7/1/2020

@Ron I’m currently having the same issue. (2002 GMC Yukon) No power from the green wire. Which is effecting the trailer right turn, and brake lights.

Steven S.

8/25/2021

@D likewise. Car right turn light works but I'm finding that bot right and left turn signals turn on the left trailer turn signals. Now what?

See All (4) Replies to Ron ∨

Joe H.

3/12/2024

I have led taillights my right turn not working every thing else works

Mike L.

3/14/2024

@JoeH Is power reaching the taillight? Is it showing up on the right turn signal pin on the trailer connector with the right turn signal activated? I'll link to an article that shows which pin to check....

Helpful Links

faq-wiring.aspx

Dale D.

5/23/2024

Broke tail light on trailer, replaced with new. On left turn signal all the 4 way lights come on trailer but on right turn signal no lights come on trailer and on the 4 way flasher all lights come on trailer. DO YOU HAVE ANY IDEA WHAT IS CAUSING THIS? Everything was working ok before I replaced with new.