First thing to check is the switch cluster is o.k to remove it get a thin bladed blunt knife a small kitchen pallet knife is ideal carefully insert it between the rear of the cluster and the door trim and ease the switches out. Disconnect the multiplug by lifting the small plastic lever. remove the base of the cluster it is held in place by plastic tabs. Examine the contacts on the rubberised pad and make sure that it alligns correctly with the corresponding switch contacts. Try it before you replace it back in the door and keep your fingers crossed that you have just achieved an easy fix