How to Determine the Wire Functions of a 4-way on a 2002 Buick Regal

Question:

Instructions say I have a YELLOW, Green, Brown and White wire for Ground. I only see a BLACK, Green, Brown and White wire for Ground. Do I use the BLACK Wire in lieu of the YELLOW Wire?

asked by: Don M

Expert Reply:

Most likely you would just use the black wire in place of the yellow wire, but I would recommend you wire by function that way you know exactly what is going to what. If this 4-way is on the vehicle connector I would use a circuit tester like our part # PTW2993 and test the functions on the 4-way by having a friend apply the different taillight functions and then use the circuit tester to see which wire has power. Check out the video I attached that shows how to do this.

Now to test the wires on your trailer you could trace the wires of the 4-way to see where they terminate, or you could apply power to the different circuits to see what each wire does.

I attached an FAQ article on trailer wiring for you to check out also.

expert reply by: Jameson C