s500 hydraulic power door closer problem
 

My driver's door power closer has stopped working even though the other three doors operate properly.

Could anyone shed some light on what the probale fix would be for this problem?

pull fuse #9 in the trunk for a few seconds see if the pump resets and allows the door to work, if it does, it means either the pump may be defective or that door vacuum circuit may have a leak. they operate by vacuum, not hydraulics.

search on "closing assist" or on another forum http://www.benzworld.org/forums/forums/thread-view.asp?tid=1203330&posts=35&fid=13

W140 Door Closer wont work
 

I am having the exact same problem on the passenger door of myb 97' S320. The reply to this thread helped me understand that this could just be a vacuum leak. Can anyone please tell me where in the car the closer pump is located so I can inspect that for leaks.

Closing assist
 

There are two schools of thought. Number one is that there is a leak, number two is that the latch mechanism is stiff. The pump has safeties and will disable a door or trunk if it can not sucessfully perform a latch in two tries. I am on my second pump and they never found a leak. Some people have tried modyfing the safety, I have pondered adjusting the latch so it latches before hitting the pressure safety. It is working and untill I have isues wont do anything. If the fuse trick works you can get some extra use, but as I found out once it stars the others will act up.