Installing 7-Way Wiring Connector to Trailer For Reverse Light Function

Question:

Hi. I bought this 7 round harness for the car and the trailer and hooked up everything but the backup lights. Now I went back to hook up the backup light, which has red/black/white wires. I got the purple wire on the vehicle side hooked to a backup light. It works but what color is the center pin wire on the trailer? There isn’t a purple wire on the trailer harness. Thanks.

asked by: Michael J

Expert Reply:

The center pin on your 7-way on the trailer side is the reverse light function. These can be different colors, which I get is confusing, but you will need to do some deductive reasoning or use a circuit tester to determine the function and color. For instance the yellow wire on the Hopkins # H20044 or the Bargman # 50-67-008 is the reverse wire which isn't the norm because the yellow wire is typically the left turn and left brake wire. I've attached a photo and an article to assist.

You can use a circuit tester like # PTW2993 to determine the wire function when connected to your vehicle side 7-way.