My two cents. When I bought my EOH trailer, brakes worked fine until a couple of weeks later. Found out my controller wasn't EOH compatible & it couldn't handle the amperage. Put an EOH compatible controller on & it still functions 4 years later.

Update to the story... Back at the lake this weekend and as mentioned in a previous post I do have power at the 7 pin on my truck. I connected the brake harness today and when you manually move the brake controller I can hear the pump kick in, I can also hear it when the brake pedal is pressed. The the pump is working but I still have no brakes on the trailer. Any suggestions on where to go from here?

Air in the line? Low on fluid?

Checked brake fluid still full, Bleed the brake lines with the controller held over to 5 its highest setting. Still no brakes. A friend suggested the seals in the pump may have deteriorated to the point it cant build enough pressure could that be the issue? System is a Titan and its 15 years old. Bleeding brakes with the controller set at its highest point I would think would be the maximum amount of pressure to the caliper.

Had similar issue. Check tow vehicle trailer power fuse.