brake controller output

thanks. wiring is not the issue. There are just two wires that are hard to mess up, unless the wiring is shorted to itself there is nothing left there. I did put new wire in, bypassing the trailer wiring, I put two wires at the plug and went straight to the brakes. 4.x volts, but no action at the brakes. Is 4volts enough? 5 is supposed to be the max it puts out.
I tested magnets individually and one worked fine and made the brake work, another did not work - just made a whining noise, did not test the other two, gave up and ordered 4 new magnets. we will see…