How do I check the wiring harness connection? As of today all interior and exterior lights including brake lights are working properly. But camping this past saturday all were out with a weak camper battery of only 5.68. Thanks for any assistance. Also, the brake controller unit is still not working properly. So for now we have just disconnected the unit from under the dash in our Nissan Pathfinder. Is any of this related?
- I bought one like this to quickly test the OUTPUT of my truck's connection:
https://www.amazon.com/58270-7-Way-...1045870&sr=8-3&keywords=trailer+wiring+tester If everything checks ok, then your problem(s) are on the trailer side of things.
- I take it you are not plugged into any power last Saturday? If you are running 100% off the battery over a weekend, then you can easily run down a battery if not being careful. Either way, that battery may be shot, and getting a new one will help figure out where your problem(s) are.
- I'm not sure why you'd say you don't have any brake lights while camping, once disconnected from your truck, you SHOULDN"T have any brake lights on!
- You don't want to drive too much without that brake controller working!
- All of these issues are VERY hard to comment on without knowing what your power source is when things are not right.
Are you A) Connected to your truck,

Connected to shore power (30amp/110v) or C) DISconnected from your truck & with no 110v, and running 100% off your trailer battery. Which of these three really matters.