I hooked onto the neighbors 04 featherlite stock trailer and my 05 F350s brake controller would read "trailer disconnected". His trailer had the round 6 pin connector and also the brakes on the trailer would lock up when the harness was connected. So I had to go without lites. Just wondering if anyone would have an idea to what the problem is? If it is a grounding issue then does it ground through the harness or on the ball only?

 

If the trailer brakes are locking up right when you plug the trailer into the truck,its a good bet that the plug is cross wired for 12 volt and brakes.
Take the 6 way apart on the trailer and see what wire is hooked to what pin on the plug,blue should be brakes and black is 12 volt.Swap the two wires out and then plug it back and see what happens.
When you take the 6 way apart it will have letters for each function (TM= Tailmarkers, GD=Ground, LT=Left turn RT= Right turn etc.)

This happens on some trailers and you have to switch the wires,sometimes it happens cause on some trucks the truck plug is wired that way,brakes and 12 volt are cross wired.

Never rely on the trailer to ground through the ball the wiring harness on the trailer should be grounded itself and the plug on your truck.

Dan

 

Dan is correct.

You need to take the cord end apart and switch two wires. You need to switch the wire that is going to the center post and the wire that is going to the side "AS" post.

In the past some trailer mfgs would use the center post for brakes and some would use the side post. The problem is at the same time some of the manufacturers that used the side post for brakes would use the center post for a hot (constant) power source. If your truck was wired for this and you hooked up to a trailer that was wired for brakes on the center post your brakes would lock up.

 

Yup... that's why the adapters have movable pins for those two wires. There is no standard for six pin plugs, unfortunately.