i had the problem where the motor would click, and there were no problem with any of the wiring.
Turned out that the clamps holding the windows in had been pushed to far up on the rails and was catching at the top, so it was impossible for the motor to bring them down again. Didnt realise this until i had taken everything out, and trust me its not an easy job getting it out whilst you carnt move the window down!, i'd buy a new regulator and rails in readiness, and cut the wire of the one in the car to take it out, then just swap.