Is the sensor for the auto wipers located with the light sensor behind the mirror or is it electronic contacts elsewhere on the glass? The wipers were given a clean bill of health recently but Im still not happy with the way they operate, has anyone else had any issues with their sensitivity? anyone else had problems when using screen rain treatments?:(

The rain sensor is indeed behind the rear view mirror as you say.

I always found my rain sensing wipers to be pretty spot on.

The rain sensor is located where mirror is glued to the windscreen (in the center area).

Look inside and will see some infrared LEDs surrounding photodetector.

When you say 'screen rain treatments' I assume that you are talking of RainX/Rainaway, or similar. When I bought my Octy I 'persuaded' the dealer to throw in an Autoglym treatment. He had obviously studied the stuff and pointed out to me that the side and rear windows would be treated, but not the windscreen. Apparently Autoglyms view is that it will affect the wipers. Perhaps there may be some connection? I certainly have no problems with my auto wipe, I just leave them on and they deal with anything from light drizzle to downpouirs at 70mph.

My auto wipers have always been spot on until.... I used a polish style glass cleaner two months back!!! Its now all over the place in terms of wipe action - used to be very accurate but now its not. Didnt think about it at the time but the cleaner has obvisouly created a barrier across the sensor, causing it to be less sensitive/confused! I'll be de-treating it next wash!

Lee

My Auto-wipers are fine and i use Rain-X windscreen treatment.

What sort of behaviour are you seeing?

IIRC the sensor works using infra-red to detect the presence of water so anything that leaves a film of water over the sensor will cause problems.

The only time I have had any problem with sensitivity is when a bit of debris gets under the blade and it leaves a trail across the sensor; or when the screen is greasy and the sensor is not getting wiped dry.

Sometimes they are a little reluctant to start - especially if car is started with wipers already switched to auto. Just need a kick by flicking the sensitivity switch and they sort themselves out.

The rain sensor is very complex device. The photodetector is a CCD device.

There is used sophisticated image processing to detect rain drops.

It will signal only when detect difference in the rain drops configuration on the analysed area.

The rain sensor is very complex device. The photodetector is a CCD device.

There is used sophisticated image processing to detect rain drops.

It will signal only when detect difference in the rain drops configuration on the analysed area.

Yes, maybe on Merc or on some other premium cars, but on VAG cars it's a simple photodiode/led device.

There are leds that emit light to the windscreen. The light emits back to the photodiode (located in the center of the rain sensor device). The amount of reflected light is the key. If the screen is clear there's most reflection, when wet, minimal reflection.

When I got my new car a was very intersted in finding out how this worked, found this which explained it for me!

Alan

they have failed on SWMBO's Golf GiT for the second time this week, last time both stalk and sensor were changed ......who knows this time....

We had to have the motor changed when ours acted up. Sensor was sending signal to turn motor on, but motor chose when IT wanted to work unless on hurricane mode (full).

Mine are quite crap to be honest. The wiper speed is all over the place when it rains and it usually defaults to monsoon speed whether I like it or not.

The sensor is pretty basic as flickering sunlight can trigger the wipers every now and again.

Mine are quite crap to be honest. The wiper speed is all over the place when it rains and it usually defaults to monsoon speed whether I like it or not.

Are your wiper blades in good condition? If the passenger side blade is not wiping the sensor area absolutely clean then it thinks it is raining harder than it is so will speed up the wipers.

On the Golf, sensitivity adjustable via control stalk.

Also they speed of wiper is dependant on car's speed.

Most of the time wipers are spot on in my car.

Mine were working well until I had to have a new windscreen fitted (due to a stone chip in the old one). I made the repairers aware that the car had automaitic wipers but they still seem to have mucked up the sensor area.

Since then the sensitivity seem lower and the windscreen often gets heavily covered with raindrops before the wiper kicks in.

Thanks for the comments guys, I have used Rainex and then MER rain treatments on the screen. Yesterday I gave the whole windscreen a good clean with Autoglym glass cleaner paying particular attention to the sensor area, cleaned this area 3 times!. Then retreated the screen with MER after I had put masking tape over the sensor area. Seems to be much better now, time will tell! Maybe there IS something about using screen treatments affecting the sensor, previously my wipers began ok but ended in Hurricane mode whatever the rainfall, even wiping a dry screen.

This is a known problem, there are two different sensors and the newer ones should be better.

Skoda knows about the problem, here in Germany you can have the old one changed under warranty.

This is a known problem, there are two different sensors and the newer ones should be better.

Skoda knows about the problem, here in Germany you can have the old one changed under warranty.

Any idea if theres a different part number between the new and old or whats the best way of distinguishing between them?

My sensor was perfect until the windscreen was changed.

Are your wiper blades in good condition? If the passenger side blade is not wiping the sensor area absolutely clean then it thinks it is raining harder than it is so will speed up the wipers.

I change them every 15,000 miles so no problems there. I always make sure the sensor area is nice and clean but they still go like the clappers

The newer one has 4 diamondshaped spots inbetween the sensors.

This should be the partnumber (I have it out of a post from Theresias in the german forum)

1K0-955-559-AB

The newer one has 4 diamondshaped spots inbetween the sensors.

This should be the partnumber (I have it out of a post from Theresias in the german forum)

1K0-955-559-AB

Also one from our own diagnostic area :

http://briskoda.net/diagnostics-vag-com/rain-light-sensor/104559/

Do we know when the improved sensor was fitted from?

I had them on a Renault Scenic (and other cars) and I absolutely hated them. They never work the way they should.

When I got my Octavia last year I was asked do I want sensor wipers. The chap was a little surprised when I told him I would rather stick hot needles in my eyes.

The standard wipers are much better, and easer to control.

The standard wipers are much better, and easer to control.

But you can run them manually still