4 pin vs 7 pin trailer harness
 

I've been wonering what more a 7 pin powers than a 4 pin. My new trailer only has two tail lights but has a 7 pin plug and was wondering why.

Here you go.

Attachment 185560

Mostly used for trailers with electric brakes.

My boat has a surge break on it. In order for you to back it up you need a five wire plug. I installed a 7 pin connector and used an adaptor for it. The 5th wire releases the brake when your in reverse.

The extra pins cover whatever you need. For trailers, that is usually electric brakes. There can also be an "always on" 12volt feed that keeps the trailer battery charged.

The 7 pin is also useful when you tow the Jeep. Same basic setup: 4 wires for left/right/run/ground. 3 more for brakes, 12V charge, and a spare.

The 4 pin to 7 pin adapter I bought has two bullet connection wires coming off the loom and a white (ground) loop. Since my trailer doesn't have electric brakes I could probably run something else to the trailer, like bright rear lights, etc...