I have a 2001 E430 and the driverside rear door won't unlock with electric locks. These locks work slower they dont just pop up like on most domestic so I think it may work on some type of vacuum. Does anyone know what might be the issue?

 

Tex,
I have the same problem on my pass rear side. I've been living with it for about 1+ years now. It will lock but won't unlock. My indie mechanic checked it out and identified good vacuum but a bad lock actuator. Approx $260 to fix. I can live with that. Pull out your rear seat and put the remote in your hands. Go to a quiet area first, then cycle the locks and listen for a hissing sound or whatever. If you can't identify the issue from a leaking hose or whatever near the battery (mess of yellow cables going into a box is your vacuum box), then you may have to make a decision... get it fixed by your mechanic or live with it. Good luck.