Troubleshooting 4-Pole Trailer Connector-Turn Signals and Brake Lights not Working

Updated 09/09/2014 | Published 09/06/2014

Question:

all my lights come on but I do not have right/left turn signals or brake lights I cleaned the ground wire area and attached the wire with a new clip. Do not have any meters to check circuit or power source. I purchased from you a four wire set with a white/brown/yellow/green connectors

asked by: Isaac S

Expert Reply:

What's the year, make and model of your vehicle?

A vehicle can have one of two different taillight set-ups, a combined or a separate system. On a combined system, both the brake lamp and turn signal are carried on one circuit, just like the wiring on most trailers. This is a very simple wiring system, that allows you to simply wire in a connector like the # 18004 connector you mentioned.

On a separate system, the turn signal and brake lamp are on separate circuits. Take a look at your taillights. If your car has an amber lens for turn signals, you have a separate taillight system, and simply using the 4 wire trailer connector like the # 18004 wouldn't work. You'd have the same type of problems that you're mentioning.

If your vehicle has a separate wiring system, you'll need to use a taillight converter. A converter will take separate signals from the brake lamp and the turn signals, and combine them onto one circuit for the right and left side of the trailer.

If you can reply with some information about your vehicle, I'd be happy to provide some specific troubleshooting information for you.

expert reply by: Mike L