W204 estate - rear wiper issue

[dibblodocus]

Hello all,

I hope I am posting in the right place for this one....to do with the rear wiper on my W204 estate.

Occasionally I have noticed that the wiper goes beyond the 'end point' of its normal arc, or doesn't wipe far enough, i.e. for some reason the normal arc of travel is not followed. This is intermittent which makes me think it is a control (electronic) issue rather than mechanical....but I could be wrong.

Does anyone know what controls the arc of travel on the rear wiper mechanism? What can I check to try and diagnose the problem?

Thanks in advance.

 

[Dec]

Are you saying that the wiper blade is going off the glass and down on to the paint work?

Dec

[YOUTUBE]GjG47NepSWM[/YOUTUBE]

 

[dibblodocus]

Occasionally, yes, but not by much. And sometime is stops or hesitates part way across the screen - much the same as your video.

 

[Dec]

The wiper arm might just be slipping on the wiper motor shaft, you could try reseating the wiper arm, a similar job to the one in the video below.

[YOUTUBE HD]R8billqJyeA[/YOUTUBE HD]

• Be sure to run the wiper… turns ON and then OFF at the wiper switch… before you remove the arm, this is to allow the wiper motor to finish its cycle and park.

• The wiper blade might or might not park where it is suppose when the wiper motor finish its cycle, however you will be positioning the wiper arm in the correct place at the bottom of the window before you tighten up the nut.

If that doesn’t cure the fault then the problem might be with the wiper motor, you would have to remove it and open it up to inspect the internal mechanism and gears.
Not your car but this might be of some help, see… W639 Rear Wiper Motor Repair and Modification - Mercedes-Benz Forum

It sounds a bit like a mechanical fault but it could just as easily be an electrical fault so fuses should be checked the wiring to the motor and any wiring at the tailgate door hinge.

Dec