heater control unit wiring and cables Options

[dt4]

What a job that was, getting all the heater / ventilation components into the front trunk and under the dash and the cabling into the cabin was an absolute bitch of a job.
I then realised that it was not possible to fit the cables to the control unit whilst they were fitted to the ventilation flaps so i had to disconnect them, fit them to the control unit and then feed them back through to the trunk and refit them to the flaps
The middle control slider was really stiff to operate and forcing it resulted in the sheathing pulling through so it will need to come out and be re-attached, the cable must have been at the wrong angle to be so tight.

The other and problem i am struggling with is the electrics
The control unit had remnants of the wiring still connected and the wiring loom had the corresponding pieces of wiring, I therefore thought reconnecting the white/yellow to white/yellow and the white / green to white/green etc... would be all that it needed
Wrong, no power to the unit although as soon as I touch the white/yellow to earth the fan starts to run
There is an earth cable to the unit so I am puzzled why earthing the white/yellow instead of fitting it to the connector that it came from makes it run

I am pretty clueless when it comes to electrics so please keep it simple (IMG:style_emoticons/default/beerchug.gif)