Earl, no, I should have mentioned that. What I mean are the microswitches in the 3 lock cylinders. I assumed (never a good thing to do) that it isn't working any any lock (both front doors, nor the trunk lock cylinder). If you're not sure, I'd plug it back in and check out what works and what doesn't. If the system is inop at only 1 lock, then I "take back" previous comments and suggest instead asking a knowledgeable, competent, helpful MB tech if he can fill ya in on checking out a switch instead of playing with the pump