(G) Rain-Sensing Wipers (or Automatic Wipers)

Well I have always wondered how rain-sensing wipers work... and today I finally found out as it rained while I was driving my Stilo... they don't!

It reminds me of the whole idea of TV ratings (which I abhore) - statistics makes the assumption that if a test group of people watch certain TV programmes, the total number of viewers can be extrapolated.

Anyway this same principle is obviously being applied to a tiny sensor in the windscreen glass, which is supposed to be representative of the water falling over the whole windscreen. Hardly! What if there is a blob of water on the sensor and lots everywhere else, or the same blob and hardly any rain elsewhere...

I think possibly another factor, since the sensor lies within the wiped area, is when the droplets are broken up into tiny drops by the wipers... The blades are in good condition and the glass looks clean, but I wonder if it may be suffering from a buildup of wash'n'wax or automatic carwash 'hot wax' (previous owner used carwashes, I don't).

Anyway, if you'd like more of the detail, I'd been leaving my wiper stalk at the first click. It started raining, and nothing happened, so I moved the stalk to 'off' and back to 'auto'. (Surely not very 'auto' if you have to turn it off/on each time it starts to rain?) There was a single wipe ("acquisition stroke", as the handbook calls it), and then a few seconds later, another wipe! Yes!!!

Then there was a wait of approx. 20 seconds (during which the screen was totally covered) and then a double-wipe. The interval now seemed to be only a couple of seconds, then there was some clicking and the wipers started on continuous, full-speed!

Things got really interesting as I approached a busy roundabout (well, with all the downchanging, indicators etc. busy for the CAN bus, at least). The wipers, which had settled down to one double-wipe every five, suddenly stopped altogether just as the rain set in harder. I could hardly see, but I thought that manually over-riding it would be cheating. I drove through anyway, hoping no-one was there (they weren't).

These cars have a lot of human character built in (and erratic Italian character at that ) I always thought that the 'Auto' mode of the Selespeed was like having a blindfolded passenger operating the clutch and gearlever. Now, I think Automatic Wipers are having the same blindfolded passenger operating the stalk, listening for the rainfall.

Cheers,
-Alex

I have never found the auto wipers on my Stilo to be effective [although others have] - so I just ignore them.

YET the ones on the Ulysse work perfectly, and I never have to fiddle with any settings at all

Yes, I noticed - in your older threads I think the conclusion was that it was because the switchgear wasn't made by FIAT!

I think that cleaning the glass may effect an improvement - now just have to think of what to clean it with... 'wax and grease' remover for painting?

And also, I'm thinking of taking the headlight stalk apart and defeating the interlock (the one that prevents you from moving to high beam with the turn switch on 'auto', 'off', or 'sidelights'). It's probably a safety feature - to prevent the lights being left on high beam - but if so, they should have made the high beam a 'soft' (computer-driven) function (one-touch switch, rather than latching - like the heated rear window), like it is on the Vauxhall Corsa

-Alex

I think Stu has summed this up quite well.

Mine are close to perfect but I know others complain about them

The action is:
One click down to initiate wiping and then up again which will leave them in auto mode. You can change the frequency a little with the 3 position selector although I rarely bother.

I've found the system can be left in auto mode for hundreds of miles of motoring and will take account of every type of weather from a light drizzle to a torrential downpour

No probs with mine either but then we have 5dr stilo's

I had similar issues to Alex on my mum's 5dr when I used to drive it. In the end, I got a new sensor fitted under warranty (there was talk about it having delaminated, and the sensor was updated mid-2003, so I demanded a new one ). Since then, they've been brilliant, and the problem with the screen being covered in millions of tiny droplets before the screen wiped went (maybe the old sensor took the size of droplet to work out the wipe frequency and the new one takes size, occurance rates e.t.c. and gets a more accurate idea).

As for the Ulysee, don't they have two sensors on the bottom of the screen for auto wipers? I think the VW Golf uses the same sensor as the Stilo does.

Alex, your query about the stalk. Indeed, the Megane for example doesn't have this, although to be honest I found it a good idea. It's a safety feature; let's say you've got your ignition on, didn't think about the wipers, went to change them or remove a leaf from the window and they come on; could cause an injury. Seems far fetched I know but at least FIAT have thought it through. The Ulysee no doubt takes it's switchgear from its French designers!

So yeah, that.

One of the worse features of the Stilo in my opinion. Sometimes they worked flawlessly other times they were awful. The Alfa has a much better system, manual control with intermittant wipe speed control. And yes the main beam lock is very very annoying.

Again, mainbeam is locked out so that when the automatic lights are activated they don't automatically engage full-beam lights. If people weren't so stupid there would be no need for these anti-stupid devices

And again, the Ulysse gets it right, by allowing mainbeam even with auto lights on.

I now turn off auto lights on the Stilo. But a lot of my driving in the winter is based on country roads, so I need full beam quick, without having to fart about.

Quite, my Stilo hasn't got the comfort pack fitted, the only thing I miss are the parking sensors!

I don't need these nanny devices fitted to the car sounds great in the broucher but doesn't work as it should. Compared with the Stilo Abarth the Alfa 156 is relativtely free of toys and gadges and the better car for it. Technology is great when it works if it gets in the way it shouldn't be there.

the rain sencing wipers work by mesuring the amount of infared light on the inside of the screen and on the out side as water reduses the amount of infa red

if you press the mode button you can scroll throu the menu to set up the sensitivity

if this dosent work then something might need replasing

i dont believe anything on the screen will afect the way it works

lots of people use rainex for instence and all sorts of wax products

Since mine and PNL's are both 02 models I think you can discount the update - so perhaps it WAS a lamination issue.

I have to say the technology on the Stilo works fine for me

I can't understand all the fuss about auto lights. If you don't like them then don't use them - quite simple really - hardly ever use mine for the simple reason there are very few tunnel systems where I live so I don't get the chance.

Too true Jason, best was going into carparks and them coming on . It's like my new CN+, if someone gets in the car who hasn't seen it yet I always use the Voice Commands to get the CD player going

I asked the dealer to look at the rain sensor and they did something like replace and stick it back on can't remember exactly. This would have been 03/04 - sometimes it was fine other times you'd be driving blind before it worked it out. I'm sure the droplet size had an effect, can't remember which type was best think it liked large rain droplets rather than the fine mist type. If it got it right 100% of time I would have liked it but with no override for normal intermitant control it was an irritant and a hiderance. At the end of the day a flick of the wrist and my wipers are on. I spent more time playing trying to make the "automatic" wipers work effectively and I like to see where I'm going too.

As for the autolights, I liked this feature but why lock the mainbeam out? I think I have enough intelligence to work out how my lights are set, I don't need child locks

Features I did like were the cruise control and parking sensors - general useful tech although the cruise control almost killed me and the missus once - being tired and cruise control don't mix.....