Locating Reverse Light Circuit on 2003 Dodge Ram

Published 03/06/2015

Question:

Is there a diagram/document or can you describe to give my truck guy to determine what wire from my Dodge Ram 2003 truck backup lights is used to put in my new 4/7 wire truck tracker harness to deactivate the trailer brakes on backing up on my 5 wire trailer? this is the one I just got from you: 20135 Multi-Plug T-One Connector Assembly for 7-Way and 4 Pole Trailer Connector. I have a 5 from trailer to 7 wire converter plug I use from trailer to truck to go into the 7 round that will be on the truck.

asked by: Alan W

Expert Reply:

In my research, I saw several mentions that Dodge liked to use a purple wire for the reverse lamp circuit. However, I wouldn't recommend taking this as gospel. The best practice is to wire by function, not by color. Unfortunately, I don't have any documentation of wire color codes.

The # 20135 you referred to plugs into the tow package wiring. The wire in the harness behind the 20135 that connects to the center pin of the 7-way connector will carry the reverse light circuit, so you can obtain the signal there. If you use an adapter like part # A75TB, you shouldn't need to do any splicing at all. The tow package wiring on the truck should already be tied into the reverse lamp circuit.

expert reply by: Mike L