Door closing assist (not locking)

I just had mine checked-out at the MB dealer. The "elements" at the trunk and the doors tends to develop leaks. The main pump (located in the left wheel well section of the trunk) will quit trying when it detects significant vacum leakage at the elements. SOlution: Replace the two elements in the trunk lid, and the one-each at each door if needed. If you haven't burned-up the main pump, you're back in business. If you have burned it up, then it needs repacement also. BTW, how much? : the two trunk element and the main pump cost me $1500 to repair, and each other door element will run about $200 each with labor.