Found this corroded trailer socket on mine … I thought “no big deal” but surprisingly this pin does not work w voltage meter or trailer.

The connector was full of water. For I guess the past 18 mos?

I think I can clean it up further or use an adapter on the round RV plug for this weekend’s towing project. But just plugging in / unplugging the harness yielded no lights

but might be worth chking yours…. Before you are at U-haul!

 

Thanks for the heads up. Will definitely check mine out.

 

Okay - so what is that 3-lead connector next to the 7-way plug socket?

 

It's hard to see, but it's four. Three pins are one type, and the fourth is an odd type. I used it with a lights only trailer. The 7-pin has the brake communication if you have a brake controller installed.