Windshield wipers stopped working



My wipers used to occassionaly stop working...over the last 2 years the problem just became more and more acute, until recently where they have almost stopped working.
With me, the problem is they now only work on the highest sweep speed setting..all other settings are dead. I am guessing, its not long before they completely stop working, and so it will have to be fixed in the near future.
Yes, there is timing relay in the fuse box for this, and I have tried replacing it, but no help. Dealer has quoted $480 for diagnosis and a possible wiper motor replacement.
Does anyone know of a DIY on the wiper motor?
And yes, what a coincidence...we are both talking about the exact same model year and model..2000 ML320
Last edited by mihir_d; Jan 5, 2007 at 04:15 PM.



My suggestions is either to buy a naughty copy of the WIS on the Internet or or to search http://www.whnet.com/4x4/
There was also a Tekinfo (????) web site from where you could download manuals for a reasonable subscription - but sadly I have lost the url.
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BTW, me too, I am done with checking and even replacing the relay and the fuse. That hasn't helped.
I have an appointment with the dealer for Saturday Jan 20th...and so, I'll let you all know, what the dealer finds..



Anyways, the motor will have to be replaced....$557..
Its a special order part...will have to reschedule an appointment to have it replaced...
I am still surprised, no one has any idea of how to DIY...if I happen to standby and watch my mechanic do it...I will try and post some instructions on it.
Not a common problem on the ML, I am told...its rare to have the wiper motor fail this way..



I did a lot of research on the internet on wiper motor problems...and the only other vehicle that seems to have the exact same problem is the Ford F150.
One moment I thought, it might be a common wiper motor supplier between the two that might be source of the problem...but the conclusion on the F150 is that there's nothing wrong with the motor, its the design of the wiper system by Ford engineers on the F150 that is the problem. The motor is installed on a frame member of the truck...which means all vibrations are passed on to the motor.
The motor is not designed to withstand those kind of vibrations...and is not supposed to be installed on a frame member..
The parking circuit is typically the weakest part of the wiper motor...and it just cracks by the vibrations...Ford F150 owners have managed to get to the wiper motor and just re-soldered the parking circuit board to get the motor to work again...
I am wondering if MB made a similar design mistake in designing the wiper system..



The wiper motor replacement involves more of special tools rather than expertise...the front hood had to be decoupled from the hood struts to let it open further wide up.
The wiper arms were unscrewed using a special MB tool..and the black cover at the bottom of the windshield was snapped out, again using a special tool. I believe it was the power steering pump somewhere right on top near the windshield that too had to unmounted to get to the motor. After that wiper motor is clearly visible.
The wiper motor is mounted wierdly upside down in the center of the 2 wiper arms, screwed to the car body by 3 screws that needed another special tool to unscrew. There is an arm and gear assembly that transfers the motor drive to the wiper arms.
The wiper motor itself is quite heavy (made by Bosch in Mexico) and seems to have its own electronics for sweep speed settings and a gearing mechanism along with an eccentric that converts the rotory motion of the motor into the swing for the wiper arms.
All in all it took the mechanic about 2.5 hours to complete the job and I just noticed today that he has accidently reassembled the hood struts upside down...they are unable to hold the hood even for a second..the hood just drops down. I will have to call in tomorrow, and take it back to have it fixed.
Otherwise, my wipers are back to normal..
Unusual for the wiper motor to fail though...it shouldn't have happened in the first place....
Last edited by mihir_d; Feb 11, 2007 at 09:59 PM.



