Ford Focus Mk1 - Drivers side electric window fault?

Hi, I bought a Focus over the weekend and I was aware that the window was not working, I assumed it would be an easy fix.

The Drivers side switch works the passenger window with no problems, but when you press the drivers window button nothing happens, the motor doesn't even attempt to work.

I have checked the fuse and they are fused together so if ones works then it can't be the fuse.

I have taken the door panel off and tried given the motor a few taps as I've read elsewhere that this is sometimes all it needs, however nothing still happend. So I then applied direct current to the motor on the white wire which then proceeded to wind the window down, so I established the motor works going down, but then putting current direct to the yellow wire just made sparks and the wire burning a little. I used my small knowledge of electronics to then cut and reverse the wires so I could apply current to the "up" wire on the motor and at least managed to get the window back up!

I now know the motor works up and down, but there must be some problem with the wiring between the switch and the motor connector. When currents applied to the the down wire it will go down but the up wire just seems to short out.

I've also put a volt meter on the wires just before they get to the motor and there doesn't seem to be any current getting there.

Any ideas on what to try next?

Could it be the actual switch unit that needs replacing?