Rear w/w '98 C250TD

[catgate]

I still can not understand just what the precise operational sequence is for the rear w/w on my '98 C250TD auto. estate. When used simply as a wiper it wipes for about 110 degrees, pauses for some seconds, then completes the 180 degrees sweep and continues with the reverse 180 degrees before pausing again prior to continuing ad nausium. Does anyone have clue about the timing method/mechanism, please? Getting information on this is a bit like looking for intelligence in the Palace of Westminster!

 

[teky]

interesting, it is difficult to get info on it i have tried to search the net for you but nothing, since i have stripped these units and rebuilt them i can only offer advice, remove the rear plate of the wiper motor you will see a printed curcuit this tends to get covered in grease and contact is lost on it thats why the wiper stops when it shouldnt, its worth a try

 

[catgate]

Thanks for that teky. I shall delve into its bowels more fully. What you suggest does sound reasonable. Electricity is a most difficult thing to control, particulary at higher voltages, when it seems to be hell bent on finding its way up your arm.
Have you any idea of the function of the relay, attached like a wart on the top of the unit? Is this just a slave switch to handle the motor current whilst allowing the "switching" and "timing" to be done at lesser loads? i.e. does the printed circuit control the relay, or t'other way round?

 

[teky]

relay controls the wiper its a staggered wipe unit so it should do a 180 then rest then do it again, the black thing on the top im sure is just a resistor or something to that effect

 

[teky]

http://uk.msnusers.com/autodatabase/electical.msnw?action=get_message&mview=0&ID_Message=632

here is a picy of the internals just found it

 

[teky]

http://images.google.co.uk/images?q=wiper+motor&hl=en&lr=&ie=UTF-8&start=0&sa=N

infact i just found loads of stuff that might help

 

[catgate]

teky,
Thanks for your efforts.
I am afeared that the first reference gave me an old 60's Joseph Lucas ..Prince of Darkness wiper and another obscure type, apparently a front wiper set up using relay arms/wheel boxes or some such.
The second site has all manner of stuff on it, and in the words of Captain Oats (of Scott of the Antarctic fame) "I may be gone for some time!"
Thanks again.