Auto wipers

[robjmurdoch]

The sensitivity of the auto wipers on my 209 clk320 seems to be on the sensitive side shall we say! Is there any way of adjusting this, or is it just the way they are??

oh its a 52plate BTW!

Cheers

Rob

 

[welland99]

I sometimes think the auto sense wipers on my W210 are too sensitive as well. How do they do the sensing?

 

[Deleted member 6183]

Mine are too in this weather.

I think that it's the salt tricking the rain sensor.

 

[Easty]

Before Christmas my wipers were operating almost at high speed although on the lowest sensivity. This must have been because the wipers were not cleaning the screen properly at the top of the stroke.
I found that once I had cleaned the area of the glass around the rain sensors they reverted back to normal operation.
I do not think that the sensivity can be adjusted by mere mortals

 

[Rory]

It can be adjusted by Star.

Wifey's Jazz has sensitivity adjustable on the stalk but even then it seems impossible to get it right - what's fine one day is no good the next.

 

[whitenemesis]

I sometimes think the auto sense wipers on my W210 are too sensitive as well. How do they do the sensing?

They sense by shining an beam of light (IIRC, an infra-red wavelength) at an angle onto the windscreen and detecting the amount bounced back. When water (or other contaminatnts) contact the screen the amount of light bounced back changes and the wipers go into action.

Salt contamination is rife this time of year

 

[robjmurdoch]

I did think the dirt/salt could be tricking them into action! I'll just have to clean it more!

 

[whitenemesis]

They sense by shining an beam of light (IIRC, an infra-red wavelength) at an angle onto the windscreen and detecting the amount bounced back. When water (or other contaminatnts) contact the screen the amount of light bounced back changes and the wipers go into action.

Salt contamination is rife this time of year

How the Rain/Light sensor works

 

[Harley Man]

Thanks for this I have often wondered how the automatic wipers work

 

[welland99]

They sense by shining an beam of light (IIRC, an infra-red wavelength) at an angle onto the windscreen and detecting the amount bounced back. When water (or other contaminatnts) contact the screen the amount of light bounced back changes and the wipers go into action.

Salt contamination is rife this time of year

Whereabouts are the transmitter and detector? And approximately how large is the area of screen used to perform the test?

 

[whitenemesis]

Whereabouts are the transmitter and detector? And approximately how large is the area of screen used to perform the test?

Usually mounted on the windscreen behind the RVM

The area tested varies with model and age. The earlier systems (all the same principle) had a single transmitter and corresponding receiver (as a seperate unit from the ambient light sensor) approx 1sq". Later models have a set of 4 grouped in pairs either side of the combined ambient light sensor covered an area approx. 8sq".

 

[crankiejohn]

nearly wrecked my wipers i had left them on auto,when i swiched the ignition on next morning the wipers were frozen solid and the motor was bending the arms before i managed to switch off.not made that mistake since.(yet)

 

[Nickk]

This might not be the answer you're looking for, but...

My wipers only worked on fast or slow speed. Te previous owner of my W210 had fitted a non merc windscreen. Apparently other screens have different refractivity (or whatever it is) and I read somewhere here that if I disconnected the rain sensor (in the black plastic box on the screen just fwd of the rear view mirror) the brains of the car would revert to some previous incarnation and enable intermit, slow and fast wiper speeds to be selected. I did this and it works perfectly but with no rain sensor.

cheers

 

[corned]

Just another point to add to the conversation:

If your blades are getting on a bit, you may find this the reason why your auto wipers are acting oddly. If the blades are not wiping, and clearing, the screen over the sensors properly, then they will actuate much more frequently in an attempt to clear the screen.

As the sensors are at the top of the screen, at the blade's extremities, if the blades are not clearing properly across their full length, you will likely get problems.

 

[robjmurdoch]

I did look at the wipers and they are in ok codition but they may leave just a slight bit of water on the screen, enough to set the sensor off! Maybe i'll change them and see.

Crankiejohn, i did this but my wipers didnt stick to the screen the just made a horible sound as they wiped over the top of the ice

 

[welland99]

This might not be the answer you're looking for, but...

My wipers only worked on fast or slow speed. Te previous owner of my W210 had fitted a non merc windscreen. Apparently other screens have different refractivity (or whatever it is) and I read somewhere here that if I disconnected the rain sensor (in the black plastic box on the screen just fwd of the rear view mirror) the brains of the car would revert to some previous incarnation and enable intermit, slow and fast wiper speeds to be selected. I did this and it works perfectly but with no rain sensor.
cheers

I wonder how to make sure that a replacement screen is compatible with the rain sensor without going to the stealership?

 

[MrMotul]

This might not be the answer you're looking for, but...

My wipers only worked on fast or slow speed. Te previous owner of my W210 had fitted a non merc windscreen. Apparently other screens have different refractivity (or whatever it is) and I read somewhere here that if I disconnected the rain sensor (in the black plastic box on the screen just fwd of the rear view mirror) the brains of the car would revert to some previous incarnation and enable intermit, slow and fast wiper speeds to be selected. I did this and it works perfectly but with no rain sensor.

cheers

Thanks very much for this post. I have just gone from W210 Classic to Avantgarde and one thing I am sad to lose in a non rain sensing wiper! In my opinion, it never works when it should or works too much when it shouldnt, theres nothing like a good old intermittent wiper:bannana:

I will be out first thing in the morning and disconnecting it as you said,

Regards,

Terry.