SL250 R230. Manic intermittent/auto windscreen wiper.

Nile Griffith

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2009 Sl350 R230
Hi Kids!!

OK to be fair I tend to avoid taking the SL out if it's raining or looks like it's going to rain (I have an Audi A4 for that kind of thing). But strangely enough there are the odd occasions with the British weather where I do get caught out.......... who'd have guessed!!!

Any old how. A pet hat of mine is that when the windscreen wipers are set to their first position (Auto) and those first few drops of rain fall, chaos ensues!! The first couple of wipes are fine, a certain dignified period of waiting between wipes occurs. However after about the third or fourth wipe, regardless of wether there is an increase in rainfall or not, the wipers go into what I can only describe as "Manic Mode". The speed is pretty startling if honest, to the extent that I worry that damage to the wiper arms may occur.

Now I know I'm probably spoilt by the auto wipers on the Audi, which frankly are a masterpiece....... most of the time. But is there some way of calibrating the rain sensors? I've checked the sweep of the wiper blade and it seems to be covering the area of the sensor. Am I right in assuming that the rain sensor incorporates an infra-red emitter and infra red receivers that pick up the de-fracted infra-red light from the emitter that is scattered by rain drops on the windscreen above the sensor??

Any thoughts or learned ones?????
 

LostKiwi

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'93 500SL-32, '01 W210 Estate E240, 02 R230 SL500 (Malcolm Spec), 04 Smart Roadster Coupe
As far as I know the wipers can only be calibrated using STAR. The big thing is to ensure the windscreen is totally clean and it is wiped by good blades.
It may be the sensor has failed and thats causing the erratic behaviour.

And yes, your description of how it works is correct.
 

EmilysDad

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ML350
When my auto wipers started doing this shortly after getting the car, it was cos the sensor wasn't attached the screen properly.
 

SRE

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R230 SL500 2005
Mine did exactly the same thing but a quick clean of the screen around the rain/light sensor and it seems to have cured it.
 

John Laidlaw

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BMW 530d X Drive Tourer M Sports
I’ve had my windscreen treated with Gyeon view so I don’t use the wipers very much and intermittent / auto not at all...
 

flowrider

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Have you had a new windscreen fitted or was one fitted before you bought the car, if so it could be that the sensor needs to be recalibrated.
 


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