What Happens if you Mix Up Power and Ground Wire of Trailer Brake Assemblies

Question:

I have a 2017 Ram 1500 with a factory type installation controller which has worked flawlessly for the past couple years. During my recent inspection of the trailer, I found that the wires at the two drivers side brakes were broken and repaired them. My question is threefold. If I mixed up the way the wires were originally connected, would the trailer brakes still work. I read that it shouldnt make a difference. Does it?? Secondly, I tested the controller output at the back of the truck, and get power to the blue wire when I step on the brake, but not in the manual mode. My question is if I get power to the connection when braking, should the trailer brakes work? Lastly, I get the message check trailer brake system. Im guessing its because Im not getting power to the connector. It comes on intermittently, even when Im not pulling the trailer, and every time I use the manual override. My question is what could be the cause for the intermittent message, and what could be the issue if Im not getting power to the connector in the manual mode? Im thinking a short or loose connection perhaps, maybe even a fuse Im not aware of. I could use some expert advise. What am I not seeing?

asked by: Mike S

Helpful Expert Reply:

Brake magnets are not polarity sensitive so you can have either wire be the positive as long as the other is grounded and they will function just fine.

Typically the error message you are getting is due to an intermittent connection caused by corrosion on the 7-way connector pins that is preventing a solid connection from being made. If you take some sandpaper to the pins this fixes the problem in almost every situation.

expert reply by: Jameson C