Plugged in the trailer and the lights were acting weird. Determined there is no ground on the plug terminal. Checked inside the plug and contacts are all good.
I want to check where it connects to the frame.
I put a temporary jumper ground to trailer and all works good till I can find the problem

 

How many wires is your harness?

Some lighter duty trailer ground thru the ball.

On those i always convert to 5 wire.

 

What terminal do you have 3, 5 or 7? What truck model?

 

I wired the trailer 2 years ago. I wire all my trailers to ground through the plug. The trailer is not the problem.

The truck is a 95 2500 with the factory rv plug and wires

 

No trailer is supposed to have the ground path through the ball ever. There is no way to ensure a solid, consistent connection.

The flat four, and round four plugs will always have a ground wire, the white wire on the trailer side. That's the same color for the 5, 6 and 7 pin connectors too.

The ground wire for the trailer plug is the black wire according to my service manual (for a 2001 Ram). The wire should run all the way back to the battery, not to the frame. It does get spliced in with others on the way back to the battery though.

 

I will have to look at the battery for this cable.
The issue with mine is that it is only showing 6 volts at the plug. Does the power for the trailer plug go through some kind of regulator?
Thanks!

 

Mine goes thru a self resetting circuit breaker under the hood but is not factory.

Don't some trailers run 6V batteries? Maybe it's regulated power.

 

It has always been 12v except when I hauled a trailer this summer the batteries were not charging. So I checked the truck and it was just over 6 v at the 7 pin plug. I am thinking it goes through some type of regulator but do not know for sure.