Troubleshooting Trailer Wiring That all Blinks When Right Turn Signal is Applied

Updated 11/18/2014 | Published 11/17/2014

Question:

I have a 16 foot car mate enclosed trailer. I drive a 09 Toyota Tacoma, 6 cyl. My trailers lights dont work 100. When i turn on the left turn signal only the trucks light blinks, but when I turn on my right turn signal on every light on the trailer blinks. My tail lights dont work, but my brake lights do. I was told by a dealership to switch the way the 7 pin connector wires are connected to the trailer wires. I switched it to yellow to red, green to brown, blue to blue, and black to black. And Im still Having the exact same issue.

asked by: Edward W

Expert Reply:

You are having some interesting wiring issues on your trailer. First thing I would recommend you do is check to make sure all of the wires are grounded properly. Ground issues can cause bizarre trailer wiring behavior. Each lamp should be grounded either by its mounting studs being in direct connection with the trailer frame or by each lamp's ground wire being connected to the trailer frame.

Next, you will need to inspect the wiring from the connector to the light assemblies looking for any cuts or exposed wire that would cause a short and fix as necessary. It almost sounds like the right blinker circuit has shorted out to the running lights circuit.

You will need to wire your trailer's connector by function and not color since the colors can vary. You can use a jumper wire from a 12 volt car battery to apply voltage on every circuit to see what activates what and then wire the trailer connector using the diagram I attached.

I also attached a couple FAQ articles to the right that you should find helpful as well.

expert reply by: Jameson C