[Dug]

(controller) the black is positive and the white is negative. The blue on my 03 is hooked to one of the blues under the hood . I just noticed that i have two blue wires dead headed up to the fuse box under the hood. I hooked my blue controller wire to one of my blue wires under the hood and i have trailer brakes. I can take a pic if that helps you. Its prolly all different on a 06.
The moral to the story. I think your blue wire has to be hooked to the blue wire in your harness and you will have brakes. when pedal is applied.