Rear wiring for trailer towing

[sjefford]

I have a 1999 Pace Arrow Vision 36 B . And I'm in the process of installing a 7 point wiring plug to back in order to haul a car hauler. There are only 4 wires that tee off for this purpose. a yellow, brown, green and black. I believe the yellow and green are left and right turn signals , the brown is tail lights, but the black I am unsure , is it a ground? or is it an accessory power feed ?

[Gary RVRoamer]

Usually the standard trailer 4th wire is white rather than black - it's a ground that connects trailer chassis ground to tow vehicle chassis ground.

Is this wiring already in place on the Pace, or is it the wiring on whatever you plan to tow. A 7-pin Bargman connector has more than 4 wires - it also has an electric brake wire, a 12v supply wire, and an "Auxiliary" wire (most often used for back-up lights).

This web page may help:
http://www.how-to-wire-it.com/wire-a-trailer.html