2008 S204 rear wiper lives life of it's own.

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Dutchbenz

Active Member
Joined
Aug 20, 2017
Messages
74
Location
Purmerend, Netherlands deceased 26-12-2018
Car
2008 S204 C230 estate
The rear wiper does strange things. Sometimes it parks somewhere halfway the swipe, sometimes not.
This can be the motor gear dirty or worn, or one of the two relays. When I look at the fuse location table there is a relay in front and one in the rear, swapping them makes no difference.
The latest behaviour is wiping when both front and rear switches are off... it just wipes as it pleases.
Before I hunt for a new motor I want to make sure it's not just a relay, is it that simple that the front relay is for front wipers and rear for rear?
All input welcome, Tony.
 
The wiper parking issue could be down to the grease on the contacts being contaminated with small bits of copper off the contacts enabling it to conduct electricity, hence does not park correctly, a strip, clean and re grease would solve that.
For it to wipe when switch is of, it must be getting power from somewhere so I would suspect the relay is faulty,
 
The wiper parking issue could be down to the grease on the contacts being contaminated with small bits of copper off the contacts enabling it to conduct electricity, hence does not park correctly, a strip, clean and re grease would solve that.
For it to wipe when switch is of, it must be getting power from somewhere so I would suspect the relay is faulty,

Thanks Joderest for your reply, took out the relay it felt a bit warm.
I'll buy a new one after the weekend, now I have no rear wiper at all but the sweeping over a dry screen won't do any good either.
It's just a 4-pin relay so there is a chance the stalkswitch is faulty. If it's not the relay I'll take the wiper gear apart and see from there.
Thanks again, Tony.
 
Its a possibility the stalk is at fault, it you work the circuit backwards, wiper motor needs a feed to operate, the relay needs a feed to operate, the stalk feeds the relay, the relay feeds the motor.
However, if the relay is hot to touch, it would indicate to me that there is some arcing going on inside, hence it could still be your problem.
If it were me, i would change cheapest part (relay) then if still the same, get an someone to read fault codes before spending more money.
 
If its like a normal relay, the power from the stalk activates the low currant side of the relay, allowing a higher currant through the contacts, if those contacts have burnt, or fused, then its a good chance it would still pass a voltage with stalk in off position, if the relay is arcing, it could be an intermittent fault.
All guess work, but worth changing it first
 
Hi did you get to the bottom of this?

I have the exact same issue on my W204 11 plate. The rear wiper keeps parking in different locations, never past the limit and never at the same place. If I keep doing the single wipe function it will eventually stop at the correct place though.

I've read about the C10 relay which can crack the solder but where is it on he W204?

I have stripped down the motor but couldn't see anything wrong, I've greased it all up either way but couldn't try it as I had to cut the old arm off as it was siezed solid even after using a puller so waiting for the new one to come
 

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