what do I connect my auxillary wire to from the 7 pin harness.

[punisher]

wondering what in the world to connect the center pin on the harness to. If this is for backup lights, do I have to splice into my reverse lights?

[Geodude]

Yes, just splice a line in from the truck's reverse lights and run it to the centre pin of the truck's Bargman.

Then do the same for the centre pin on the trailer and run the line to the back of the trailer.

I installed $12 mini fog lights to the back of my trailer. It's great for telling people you're backing up, and great for backing into a site at night.

I have pix of my backup lights on my website, if you want to see what they look like.

[RockyMtnRay]

I would suggest adding a relay (activated by the truck's reverse lights) that actually supplies the current to the trailer's reverse lights. Especially if you're going to use moderately high amperage reverse lighting on the trailer like mini spotlights/foglights.

[onecolumbyte]

Originally Posted by RockyMtnRay

I would suggest adding a relay (activated by the truck's reverse lights) that actually supplies the current to the trailer's reverse lights.

How do I find a relay? If I walk into the local kragens/autozone is there any chance they'll know what I'm talking about? I assume it would have 3 terminals power in, power out, signal. Splice the signal wire into the reverse lights, power from the battery to the relay, to the lights. Good to go?

[cnold]

Just ask for a fog light relay. In the attached wiring diagram, a dash switch is used but you would connect that wire to the backup lights on your truck. To prevent corrosion, it is a good idea to mount the relay behind one of the truck tail lights. Seal the relay cover and connections with RTV.
Fog Light Wiring with Bosch Relay