Ok, I hope I'm not beating a dead horse, but here it goes. I went and bought a mighty vac. I first tested the lines in the engine bay. I hooked up the mighty vac to the line that leaves the check valve and then splits into two, one yellow and red(lock), and one yellow green(unlock). I then locked the drivers door with all other doors unlocked. Pumped about 30 times, all doors locked, including fuel door. Great! Then I unlocked drivers door, pumped away, nothing happened, infact the mighty max seemed to have overheated!. So then I went back into the car, hooked up mighty to hoses in drivers floorboard, once in the unlock(yellow green), all doors unlocked, then to lock(yellow red), all doors locked. So have I made any progress? I have a feeling the trouble lies in the drivers door. Thanks again guys.

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2012 550CLS
1982 380SL
1985 300D
1998 ML-320
1997 E-320
1984 380SE