Adding a New 7-Way Trailer Connector to a 1992 Ford F-250 that Previously Had a 7-Way

Updated 11/03/2011 | Published 11/02/2011

Question:

I need to wire in a 7 way plug for my enclosed racing trailer. There was a brake controller already installed in the truck when i bought it. The wiring in the back of the truck is confusing to me. There are 2 round looking plugs hanging there and that is it. Is there a way to just splice in a connector instead of having one plug directly in? What would be best, thanks.

asked by: Jamie S

Expert Reply:

What you will need to do is test the plugs you have found with a circuit tester like # PTW2993 if needed. You will be testing for the various lighting functions, brake controller output (if still installed) and a good ground. If all the signals are there and working properly, you can hardwire in a 7-Way trailer connector.

I recommend a multi-tow, like # HM48470, so you will have a 4-Way, 5-Way, and a 7-Way. What you will do is remove the plug on the end that works, clip it off, and attach the wires from it to the back of the connector as follows:

11 o'clock position = 12-volt power from battery
1 o'clock position = running lights
3 o'clock position = left turn and stop
5 o'clock position = ground
7 o'clock position = output from brake controller
9 o'clock position = right turn and stop
Center = reverse lights

I have included a link to a wiring FAQ article that may also help.