I have a 1991 420SEL and the driver's window operates slowly. When I press the down switch it does not move at all. I have to hold down the switch for a good 10 sec or more to get it to open. When it does open, it rolls down slow at first then builds up speed. It consistently operates this way. It never opens quickly like the other 3 windows.

1) What would be the most probable cause? Dirty switch or worn/dying motor?

2) If it's the switch, how can I remove it? The switch on this model and year is UNDER the wood panel. Any tips on how to get at it? The center console has a lockable storage space.

3) Any other possible causes...relays...etc?

Any help would be greatly appreciated. Thanks in advance...this is a great site!

Nolan

In most cases this is both the motor and the regulator. When the regulator starts to wear, it will cause resistance and then the motor has to work harder. Replace both and the problem is solved.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope :)
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Thanks for the reply...seems to be an expensive proposition to replace them arbitrarily. Is there anyway to test it for sure. Maybe grease the regulator? Thanks again

Nolan