Oem trailer brake controller doesn't engage the trailer brakes.

What is your question?

The trailer brake controller that came from the factory inst working when i hook up to trailers. I have a 2010 dodge ram 2500 and I have sanded the connections on the trucks connector and the trailers connector, and I have sanded all the connection points for the trailer wires. The truck has 130k miles on it and I bought it a couple months ago.

What makes this problem better or worse?

it is always the same

How long has your 2010 Dodge Ram 2500 had this problem?

ever since i bought the truck used