Scenic sunroof motor.

I've pulled the sunroof motor out and partially dismantled it to try find out why it's not working. Connected direct to car battery it works fine, turns the little gearbox freely but when connected to the wiring loom, only clicks and moves slightly when switch in fully closed position and button pressed in. Sunroof is fully closed. Any ideas? New motor unit? New switch?Thanks, Will.

Scenic sunroof motor.