hotpoint dw51 ?

hi there been havin trouble with the washing door as it will not start i though it was the safety catch thing witch is on the back side off were the door closes its an electrical switch off some sort any way i have changed that but still no joy so i by past the switch and the light on the machine came on why is there a neutral wire goin to the switch any advice would be nice .i have done a continuity to the to lives and nothin happening weather that is ok but there is with the live and neutral