Hi, to all. It seems my wiper motor believe's it's in the Indy 500 of windshield wiper racing. Slow speed or intermittent is SUPER FAST scary. The second speed its like FLASH is going by and no one in my household wants to try the third setting. A few days ago the mono wiper went so fast it went under the hood cowl got stuck and even after it was turned off it tried to free itself but broke. The piece that broke was that which, connects the wiper blade to the piece that has the two springs. Anyway a used one is on its way. How do I slow SPEED RACER WIPER down so that it does not kill itself again. I have cleaned the sensor which, slowed it down a tad bit but not much. Any help would be appreciated.

Rod

Check battery voltage at battery while the engine is running, should be 13.2 - 14.6 ish with the engine at 2,000 RPM or so. If the alternator voltage regulator has failed at full power, system voltage will rise and the motor will run fast.

If you are seeing 15.5 or more, don't run the car, you will damage electrical parts / battery.

The W210 wiper is controlled by a couple relays in the front SAM/Relay/Fuse box.

Rube Goldberg was working at MB when the W210 was designed. Oh look, we have this neat thing that was just invented, that we can use called CAN Bus, let's see how creative we can be...

Turning the wiper stalk switches several different resistance values into a control line that terminates in the ignition switch. The ignition switch reads these values and turns them into CAN Bus messages.

The CAN bus messages are passed to the Front SAM module. This module decodes the CAN bus messages and creates the relay coil drive signals that switch the motor off and on and select the speeds.

By chance does this car have the rain sensor? If the rain sensor is shot, it may think that it's raining cats and dogs all the time, and driving you to high speed. The way this works is that it emits IR radiation at a 45 degree angle to the windshield. If the windshield is dry, the IR is reflected back into the detector. If the windshield is wet, the IR hits the water droplets and bounces away. This creates other CAN Bus messages from the upper control panel to the Front SAM that influence the wiper operation.

In the evening, have a look at the upper windshield with a digital camera or phone camera. See if you can spot the IR LEDs working.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

97 should still be hard wired wiper even though CAN was in use for engine computer , trans computer , HVAC, instrument cluster. 98 got full CAN controlling lighting , windows and other things. CAN eliminates tons of wires.

Controller Area Network , this is a 2 wire communication bus invented by Bosch in the mid 80's