Rain sensing wipers - VW got it wrong

[jlbro]

I understand the sensor works by infrared, so it detects when something passes over or hits the glass in front of the sensor. I have had them go off when a small shadow passes over the windscreen on a bright sunny day.

Really? Thats sorta hard to believe - what if you drove under a bridge/through a tunnel???

[pinzvidz]

Ok well then lets just hope they work better for new corolla owners. Have you actually driven the new corolla?

I work for a Toyota dealer, and I can tell you, they're a bland and boring car to drive. Speaking of rain sensing wipers in Corollas or Toyotas, I drove an Aurion Presara the other day in the rain, and its rain sensing wipers could not make their minds up. Regardless of the sensitivity position, they just wiped whenever they felt like it, pi$$ings down or light rain. The screen would be saturated before they finally decided to wipe the screen. I tried to figure out which position on the stalk was most sensitive, and which was less, but I just gave up in the end and used them, manually.

So, all of you who think the VW's rain sensing wipers are $hit, well then try Toyota's crummy ones and then see what you think.

[Treza360]

Mine work vaguely some of the time. Sometimes they work fine. Other times they just seem to go nuts when there's barely any or no rain. Other times they just won't go when it's absolutely bucketing down.
I adjusting the intermittent setting down and then up normally fixes them up though.
Heh. Look at it this way. It adds character.

[Greg Roles]

Cool, thanks for the info people, sounds like my first mod.

[Bazzamon]

AS I've said before........You are all a mob whingers.. Just turn the wipers on or off what ever your heart desires....lol

[gtimk5]

Quite agree Bazzamon, We get spoilt these days and our expectations get higher. I am more than happy with my car. Might have a couple of slightly odd things but its all part of a mass produced car. I have had my wipers go off in the middle of nowhere at 1.30 in the morning. Pitch black apart from the golfs lights. I turned them off and then found it was drizzling outside. So how does it detect in pretty much total darkness? I know bugs will set them off if they land in the correct place.
Geez, an AM/FM radio was optional on all the Aussie Mk1 Golfs!
Cheers, Andrew

[neil]

There not 100% perfect.
Had them go off after passing under the truck safty cam at mount white
in full sun.

[VW Convert]

There not 100% perfect.
Had them go off after passing under the truck safty cam at mount white
in full sun.

Someone mentioned they thought the sensors worked on infrared, the safety cam cameras are infrared if I'm not mistaken.


Cheers

George

[jb747]

Must be something wrong with mine, as they seem to work quite well.

[acdcfan]

Mine work perfectly
I reckon your's may have a problem....

When my car is left out side in 40C ( while at work and full sun, no shade) and I sit in to drive home after, my auto wipers are goign on and off and there is no rain, so I am forced to switch them off. After 15-20 drive I put them back on to auto mode, get confirmation, and everything is good.
I doin't know what i sgoing on with them.

[Greg Roles]

Well I'm only days into the VW, but I've yet to see a problem.

The owners manual I've just read cover to cover points out how it's vital there is nothing that can refract, or bend, the infrared beam that triggers the wipers. Whilst the photodiodes ( receivers ) get the "right" amount of reflected IR light, the wipers stay off. The senders and recievers are all in that same "box". Water will reduce the reflection, and the wipers kick in.

It mentions the importance of keeping the glass over the sensor absolutely clean, and I would hazzard a guess that people with problems may be using a wax and shampoo style car wash, that is leaving a wax or similar protective residue, and altering the reflective nature of this section of glass. It mentions any sort of salt, or crystals as being a particular problem. This makes sense.

It recommends using an alcohol based cleaner, even just on this part of the screen, and that would remove any wax or buildup. Metho or prepsol etc would be the idea.

I can trigger my wipers by putting my finger over the sensor, so it's not light per say, but any change in the reflection. They have obviously tried to factor in sunlight and dark, a huge task if you think about it, for the sun emits a huge amount of IR radiation. For it to work as well at night, well it's pretty clever even if it doesn't work as people expect.

Why people are having problems through tunnels and under bridges is weird, but perhaps their glass "buildup" is on the verge of causing a problem, and a slight drop in natural Infra Red light ( the sun ) causes them to trigger.

I could be full of total cr@p , but I guess people could try metho for a few weeks just in the sensor area and see what happens.

[Splashalot]

Good points Greg, and I'll give the metho a try.

However, I can't help but think that this whole sensor-wiper invention is overcomplicating a basic safety function - IMO it's so much easier having the std intermittent wiper function which works perfectly.

SS

[THR]

Only been a few days but in Sydney it's been raining on and off. In that time the wipers have worked perfectly...

I'll monitor it over time but I did ask the serviceman when I picked up the car and he suggested to keep the window clean.

[broady69]

Don't know if anyone here has tried this but it seems to work for me.

I normally leave the switch on top of the wiper stalk to the far right position (4 I think) and 90% of the time it works just fine with the amount of rain.

Occasionally when there is a very light drizzle and they come one, I flick the switch to position 3 and they turn off.

If it then starts raining harder they will come on in position 3.

THEN

If I leave it in position '3' and it starts raining, someties the wipers will not come on and I have to flick the switch back to position '4' before they start working again.

It seems like the 'intermittent' switch on the stalk is a sensitivity control for the rain sensor to a point. Whether by design or by mistake, I don't know.

Another thing for the guys whos wipers come on in broad daylight, I've found it's normally due to shadows. If you drive under a tree and the flashing of sunrays through the gaps can set it off but mostly only in 'position 4'. I haven't experienced it in 'position 3'.

Hope this information helps becasue they used to bug the crap out of me.

Cheers

Broady

[Treza360]

It seems like the 'intermittent' switch on the stalk is a sensitivity control for the rain sensor to a point. Whether by design or by mistake, I don't know.

Yes that's what I've found as well. It's only the very odd occasion where they actually go nuts and I have to turn them fully off.