Rain (non)-sensing Wipers.

[milleplod]

The rain sensing wipers in my IS have never really worked properly - when I select them on the stalk, they only work in that mode if I give the black box near the rear-view mirror a little tweak, and then only for a minute or so till I re-tweak the box! Annoying in the extreme.

I'm sure I've read on here that if I remove the black cover and take the wire off the sensor, the wipers revert to 'intermittent' via the column stalk when its switched to 'rain sensing'. I can't find that post now. Can anyone confirm that's what happens if I disconnect the windscreen sensor please. Does the cover come off easily?

Pete

[Cracksta]

My IS rain sensor works well, make sure windscreen is nice and clean along with the rear view mirror.

I thought you can stop the sensor with the stalk by setting it to off then pull down to whatever setting you want when it rains. Theres no need to disconnect the auto-sensor?

[milleplod]

The windscreen's clean, and the rear view mirror (is that connected to the sensor for some reason?). I can switch off the rain-sensing setting on the stalk easily enough....but I'd like it to work properly when its switched on! When its switched off, I then have a choice of 'normal' speed, or 'fast'.....but I'd like some sort of intermittent operation.

Pete

[milleplod]

Well, I've had a fiddle. I took off the sensor's cover - should the sticky (that was a surprise!) pad under the cover be in contact with the glass, or just off it? Mine only seems to have the pad's top corner touching the glass, an area about 5mm square. I disconnected the sensor....the wiper's don't work at all when switched to rain-sensing - I wonder if the wires to the sensor need to be shorted out to make the circuit? I don't fancy doing that though! When I reconnected the sensor and replaced the cover, its just the same as before - when the stalk's switched to rain-sensing ('auto'), it doesn't work unless I slightly move the sensor cover with my hand!

Pete

[normski2]

Never looked at one of these.

Logic would suggest the entire pad should be in contact with the screen....assuming that is the sensor pad that detects impacts onto the screen within that area.

[jackcramerr]

can you send some pictures?

Rain sensor works by refraction of infra red light. So the diode position is vital as the light refraction changes with water droplet.

[milleplod]

Thanks for the replies.

I've just been fiddling some more. The gel pad definitely doesn't touch the screen. The sensor assembly clips into the black plastic housing mounted on the screen - there's no adjustment available to make the gel pad touch the screen (well, there's a tiny bit of movement of the assembly when its clipped into the housing, but not enough to enable the sensor to make contact with the glass). As Normski says, I'd have expected the gel to have to touch the screen, but would it need actual contact for refraction to work - I suspect not....but then why have gel, rather than, for example, a lens of some sort?? Confusion rains.....sorry, reigns!

EDIT - I've just picked up a guaranteed used one from a breaker in Dublin for £20 - if it doesn't sort the problem, they'll take it back for a full refund too, which is nice!

Pete

[milleplod]

More fiddling done! Here's some photos of the sensor removed. First one shows the gel stuff, the area in red being the only bit that touches the glass - that's explained by the fact that that corner sits slightly prouder of the housing when the sensor's clipped into it. Second one shows where the sensor fits into the housing - as you can see, there's no room for adjustment. Third one is what the reverse side of the gel looks like - complicated!

Just as an experiment, I put a piece of thin card into the bottom of the housing, then put the sensor on top of that to see if it made it 'reach' the windscreen when refitted in the car....it didn't, still only the corner touched the glass!

I'm going to have to find an IS to look at to see if I can tell if the gel makes full contact with the glass.....or if anyone can help by checking there own, I'd be very grateful.

Pete

[normski2]

I have only viewed mine through the windscreen. I've not dismantled anything.

I'd guess my sensor "patch" (for want of a better word) is the same as yours.

Its about 30mm x 20mm or so.

However, mine has a silvery line at the top and bottom edge. This looks to me much like the edge of a glue line viewed through glass. So it looks as though the pad is in full contact with the back of the windscreen.

Just a thought. Are you aware of any windscreen change? It's possible that the sensor was not installed quite right form a windscreen change. Having said that I don't know if a replacement screen comes with this fully attached.

[milleplod]

I'm pretty sure my car's had a replacement screen at some point - its the only glass with 'Pilkington' on it, rather than Lexus. I've done some digging online - it would appear that the replacement one would come with the metal mounting bracket already bonded to it, ready to take the sensor and housing. What I think has happened is that the sensor has been refitted without new gel having been used - its available as a seperate item for around £20. Having said that, I still can't see how new gel, used after the old stuff has been removed, would come into contact with the screen! It'll be interesting to see if the used sensor and housing I've bought is any different.

Thanks for the reply btw....much appreciated!

Pete

[jumbojake]

I recall my Avensis (mk2) would switch back to old fashioned (reliable) intermittent mode if you disconnected the rain sensor.... It's a shame the same trick doesn't work on the IS, as I'd assume it's the same

For my IS, I have the windscreen replaced recently... (AA windscreens) ... he connected it all back up and n problems... but I'm sure there was a 'black box' sealed to the screen near the rear view mirror... I assumed it was the sensor, but I could be wrong

[jackcramerr]

can you please post pictures of the pcb in more detail. I wish to see marking on the chips. Trying to make sense of how all this work's. Thanks.

[milleplod]

I'll post up some pics for you tomorrow - just back after a couple of days away on the bike.....and the Mrs has put petrol in her Doblo van....yes, its a diesel!!

Pete

[milleplod]

Better pic of the pcb attached - hope it'll do the job for you!

Pete

[jackcramerr]

Thanks. Unfortunately the pic isn't showing the markings. I am interested in knowing what the big chip is. It looks like a microprocessor or a micro controller given it has a crystal near by.

Do you have a picture of the other side as well? I cannot see any lense...

[jackcramerr]

I am confused on how this thing sits...

I am going to ask daft questions...

Is this the rear view mirror assembly ? That shouldn't have a rain sensor should it ? Isn't that auto dimming mirror assembly or is it a speared box ?

I am going to visually see what my car has tomorrow. There has to be a lens.

[milleplod]

Its the assembly that sits to the left of the rear-view mirror, as you're sitting in the car. I would have thought that the auto-dimming gadget would be inside the miror assembly itself, behind the glass? There's a light sensor slightly to the right of where this auto-wiper assembly is mounted - presumably that's for the auto-headlights.

I don't fancy removing the large processor for fear of damaging something. I've ordered a new gel pad, should land today, so it'll be interesting to see if that sorts it.

Pete

[Stevie P]

I had this problem...all I did was clean the sensor, didn't expect it to make a difference but it works perfectly now! I think that it is vulnerable to dust etc because it isn't sealed to the screen.

Steve

[milleplod]

Well, I seem to have sorted it! If you look at the photo that shows the gel on the sensor, you'll see its a misshapen blob - it wasn't touching the screen at all. The new pad I bought is the perfect size for the sensor, ie rectangular, its a bit fiddly to fit (you do get more than one go at it fortunatey, by putting a bit of water on both sides!), but once in place the rain sensor appears to be working perfectly! Yaayyy....as younger folk might say! :D

Here's the gel pad listing on eBay - http://www.ebay.co.uk/itm/RAIN-LIGHT-SENSOR-SILICONE-PAD-FOR-LEXUS-GS-IS-LS-RX-MODELS-/181817453470?hash=item2a552a2b9e

Well worth a go if yours is playing up - I don't know why my gel looked like it did, but suspect it was something to do with the replacement screen fitted in the past.

Pete

[jackcramerr]

Where is the sensor? I cannot understand where the silicone pad sits. :(

Is the silicone pad flexible ? Is it translucent?

Just for someone's reference, replacing the chip will not do any good. It's most probably a micro controller and a new one from Farnell will not have any code on it to function.

Good to know you made it work.

[milleplod]

The sensor sits inside the car adjacent to the rear view mirror. The silicone/gel pad is sandwiched between the sensor and the inside of the screen - its flexible and its transparent, and its the exact size of what I assume is the 'lens' - on the photo below, you can see the rain sensor without the gel pad fitted. The pad fits onto the area within the red lines.

Pete

[jackcramerr]

the pcb picture you posed, is that behind the marked red area or is it on the other side?

Have you tried holding this marked red plastic in light ? I am wondering if this is infra filter. The silicon gel is the diffuser assembly i am guessing now.

[milleplod]

On this photo, the red lines on the sensor unit will mate to the green lines in the housing - does that explain better how it fits? The 'slot' between the blue lines is where the plastic retaining clip fits to hold the sensor unit into the housing. Ignore the metal spring clip!

I've not done anything with it other than fit the new gel pad.

Pete

[jackcramerr]

thanks.