Power door locks and trunk lock on 1996 Mercedes-Benz S420

My power locks and trunk won't lock. I have to manually lock doors and strap trunk down. I checked all the fuses and changed the battery. What else can it be?

by in Richmond, VA on January 31, 2011
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1 answer 1 comment
ANSWER by , February 01, 2011
the doors locks and trunk soft-close are both controlled by electric vacuum pumps. central lock pump is under the rear seat and the trunk closure pump is in left side of trunk. either bad pump or a leak somewhere in the vacuum hose nightmare.
COMMENT by , November 19, 2012
what is the next step to fix this issue. i have the same issue with my s420 Benz. It just don't work after the head light goes out than I replace the head light. I don't understand it at all. any advise please?