Proper trailer wiring for 2006 Explorer


I’ve got a 2006 Explorer, which the most basic of the factory tow packages. It’s got an in bumper receiver hitch, and four pin wiring connector.

This weekend, I’ll be towing a very small pop up camper. Loaded, it weighs, at most, 1300lbs, and isn’t equipped with electric brakes or backup lights. Strangely, though, it has a 7 pin connector, which has wiring for those functions.

I bought a four to seven pin adapter, which plugs into the factory four pin socket, and has leads for the other signals. Since the trailer doesn’t have brakes or backup lights (and the Explorer doesn’t have a brake controller), I’m not worried about connecting those two wires.

I am wondering, though, about where to connect the aux power lead. I don’t really want to take the time to run a fused lead from the batter or fuse panel, since I’ll only be using the trailer for two days.

To further confuse me, folded over into the factory wiring sheath right behind is an unused wire. Neither it nor any of the trailer wiring is mentioned in the manual, and I don’t have a multitester. Any chance this could be an aux power connection?

Thanks in advance for your help.


I did a bit of searching but couldn’t locate any definitive information on that wire in the harness. On my Chevy, it comes with a 7 pin connector, prewired with the AUX and brake controller leads. However, the AUX power lead is disconnected up in the engine compartment next to the fuse/relay box. I suspect that if that is your AUX power wire, it is not hot. Just tucking it into the harness sheath would not be enough protection for a hot lead, especially with that level of current supply. It is probably also disconnected at the power distribution box. It might also be a brake controller wire that is built into the harness but more likely is the AUX lead as you suspect. You may have better luck getting this answered on a board dedicated to the Explorer…


Thanks… I ended up taking it by the dealer, where the ‘oil change only’ tech didn’t know… but he referred me to their body shop, where tow hitch installs are done. We studied a couple diagrams, and then doublechecked with a multitester. Your other guess was right… it’s a more or less vestigal wire that would be used with a brake controller, if I were to install one.

Thanks again.