Roland, I suggest that you pay a visit to this website:

http://www.benzworld.org/forums/

Sign in, find your model's forum, and a wealth of information will
come your way - especially for the older model M-Bs.  I've been a
member there since 2006.

dj

I haven't done a deep look into the pane wipeer motor of the W202
because mine had bitten its plastic worm gear and I had to buy a
replacement motor. That was kaputt after one year probably because I
hadn't paid attention to the inner life of the gearing. Fortunately MB
replaces any part during 2 years of warranty.

Now I had the same problem as yours with the Xenon headlamp washer
motor. It seems to have a PCT resistor in the circuit which heats up if
the motor has to work too hard for a too long time. The motor stops then
working but goes back to rest position when you start the car after a
cooling down period of an hour or so.

The basic problem with the pane wiper is to remove the friction in the
wiper gear and to avoid a too hard pressure of the blade against the
windshield.

Most of the friction comes from the worn out wiper link which happens
not to give in for the contour of the windshield.

So grease that link and the pumping axis regularly.

The second important source of friction is dirt and old grease the
excenter gear axers and bushings and the bushing for the radial pumping
wiper holder.

Remove the plastic cover and losen all screws and  clean and grease all
parts with longlife grease. If after that cure the gear does't work like
butter then replace it. Otherwise it will eat the motor.

Roland Franzius

and linkage removed.  Not a problem.  I then had the engine running with
the wiper running for another 15 minutes.  No problem.   I checked the
temperature of the motor using a small Infra Red Temperature gun, it got
up to about 115°F.   It was just warm to the touch.

wanted to duplicate the problem and see how long the wiper would run
before stopping.  So far, I've done no better than the repair shops.
This may be a real stretch, but maybe the debris removed when the access
panels were removed has somehow improved something. say cooling to the
motor.  There is a filter about 20 inches long by 3 wide, that is
filthy.  It needs to be replaced.

and any other debris laying in the tray below the motor and linkage.
Probably lubricate the linkage and reinstall the parts.  I don't know
what else to try at this time.

below the windshield had broken attachment brackets but not by me.   So
it appears, the shops must have tried to fix the problem.  I posted a
question to see if anyone has tried to repair these black colored
plastic parts using an adhesive with success.

<roland.franzius@uos.de>

or grommets where the arms pivot on all look dry.  Any idea of a go
lubiricate. I was going to use a silicon spray.   Any experience using
silicon spray on rubber parts?