Thanks for response My car is an S280 1995 model never sold in US but has the identical vacuum pump and trunk grip mechanism to the S320 sold in the States. I have just reolaced the vacuum pump which had failed and all is now OK. When I activate the central llocking system there is a short whiiir from the pump. The black tube apparently goes to HVAC which operates the grip but it still does not work Could there be a leak at the grip mechaism end located within the trunk lid? appreciate your help