Steps For Figuring Out Tail Light Wire Functions For Installing Curt Wiring Harness In 2023 BMW X5

Question:

I am trying to install Curt Powered Tail Light Converter with 4-Pole Flat Trailer Connector Item # C59236 on a 2034 BMW X5. I cant tell the vehicles wire colors for the: Left Turn Right Turn Tail Light

asked by: Kevin M

Expert Reply:

I'd be happy to help you find the correct left turn, right turn, and tail light wires for your 2023 BMW X5, but you'll have to find the wires with these functions as there's no information on wire color.

Using a circuit tester like # PTW2993 you'll need to turn on your left turn signal, and test each wire going into your left tail light till you find the wire that has power and blinks with the turn signal. I like to turn off the turn signal and confirm that wire loses power as well as sometimes wire does some weird stuff.

Repeat the above step with each function, but do one at a time so you don't mix anything up.

Once you figure out which is your right turn signal, left turn signal, and tail light, you'll hook up the following:

Green wire to right turn signal
Yellow wire to left turn signal
Brown wire to tail light

expert reply by: Samuel C