Auto wiper fault

[Mr Vlad]

My car has the auto wipers as opposed to intermittent wipe. All other wiper functions work but the auto rain sensing doesn't. Has anyone had this issue and if so what was the fault? Yes I'll be contacting the place I got it from but I'd like to go genned up.

[NemesisUK]

Have you, or the previous owner, switched the function off? On my car one can enable and disable the auto function reverting to simple intermittent operation.

Should be detailed in your handbook, if this pertains to your model. 

[Thackeray]

1 hour ago, Mr Vlad said:

My car has the auto wipers as opposed to intermittent wipe. All other wiper functions work but the auto rain sensing doesn't. Has anyone had this issue and if so what was the fault?

I had this on my IS. I thought it was a fault and was planning to report it at the next service as it wasn't a major problem. It turns out (and this may be different on your RX450h) that you can switch between Auto and Intermittent functioning. I didn't know this and had accidentally switched from Auto to the Intermittent operation when you switch the wipers on.

There's a button on the end of the wiper stalk on the IS that you press to turn the Auto wipers on or off, and a little red light turns on and off . This much I knew. What I didn't know was that if you press and hold the button, after a couple of seconds the light will flash. After the light has stopped flashing, let go of the button and you will have switched to the non-auto Intermittent option. Do the same to switch back to Auto. This only works, though when the car is stationary and the wipers are off.

After reading the manual and finally understanding what they were describing, I pressed the Auto button until it flashed and found the "fault" had disappeared. I hope this is the same fault you've got and not something needing actual repair.

[normski2]

Well I'm confuzzled here .... have to admit!!

You appear to have a 450h ... going by your avatar detail. But this is in the 220/200/250 section.

What model and year are you referring to?

There is certainly no flashing red light on my 2010 year IS250.

[scudney]

Same here 

[Mr Vlad]

Ooooops my bad. I forgot to change my car details in my profile. I now have a 2007 plate is250 SE-L. And there isn't a button at the end of the wiper stalk. Ive looked in my handbook and there's no mention of switching from auto to intermittent. 

Ive seen a couple of videos which point to the sensor on the windscreen. Ill have a look at that when I get the chance. 

Thanks for your replies guys. 🙂

[normski2]

May well be the sensor gel pad underneath that 'squelches' (great word) against the glass. 

Next time it rains have the wiper stalk set to auto. Then lightly press the bottom of the black shroud that covers the sensor gel pad. See if that makes the wipers work. (You can also get someone to spray some water onto the windscreen sensor area to simulate the same effect)

Also, has the windscreen ever been replaced? Is the gel pad missing? 

[Mr Vlad]

No idea if the screen has ever been replaced Normski. Ive yet to have a look at the sensor but I'll try what you suggest about pressing on the shroud. Because its always raining I can't tell if the sensor looks dirty or has what looks like bubbles within. 

[Mr Vlad]

Well I've had a look at the sensor and noticed a light oily coating. Cleaned that off but noticed the sensor within its casing rocked a bit so I cut a piece of card, well a beer mat, and took the sensor out then back in after the card. Solid now. Put it all together and still the same but if I moved the sensor casing either way and by that I mean 1mm or 2 then it worked perfectly. 

I've ordered a used sensor of eBay so I'll see next week when it arrives. 

Oh I didn't see a sensor gel pad. Where is that situated?

[normski2]

Maybe you did not notice the gel pad as it was stuck to the sensor screen?

I believe it is meant to have an oily coating .... I've read about that over on the US Lexus site. The account I read talked about a repair guy putting a type of oil onto the pad (sometimes referred to as a 'Tape') then refitting the whole lot. Then using a hair dryer to waft the outer windscreen face to encourage removal of any bubbles between the pad and the underside of the glass.

Attached is a Lexus pdf about the rain sensor. This may help you a bit.Again, they refer to the gel pad as a 'Tape'...odd it's more of a pad to me.

Rain Sensor.pdf

[normski2]

Found this trawling about on the net. May throw up a bit more info for you.There's that tape word again.

Where is the Lexus automatic rain sensor and how does it work?

This is located just behind the rear-view mirror attached to the inside of the windscreen

The system uses a infrared LED with a photo diode sensor.  It is designed to look for reduction of signal strength that occurs to the infrared light when a rain drop or rain droplets are present.  The rain drops lowers the signal levels by allowing the light to pass through the glass rather than be reflected back under non rain circumstances.  

 

The calibration is quite exact and can be disturbed by replacement of the windshield with an "after market" or non-dealer replacement.  The adhesive tape used to attach the sensor is very important and if not set correctly will perhaps cause the system to fail.

There is not much that one needs to do to maintain the system, as it is designed to be self checking and assumes the windshield will have the normal amount of accumulation of dirt.  However there are cases where the system can false trigger by the correct amount of dust or if the sun hits the sensor just right.

This is the sensor removed from its attaching plate.

[normski2]

Not sure how much this will help but at least you get a look at everything in there.

 

[Mr Vlad]

I've seen that one Normski found it very useful. I've swapped messages with someone selling replacement rain sensing pad which fits between the sensor and the glass of the windscreen. No such pad was seen when I took my sensor off and that picture showing rain sensing tape throws me as it doesn't show the either glass or plastic sensor plate. I have noticed my sensor plate has scratches on thats why I've bought a working used one. Ill see what happens when I get it and fit it. I'll post results. Cheers pal.

[Mr Vlad]

Success. I got a gel for the sensor and fitted it today as per instructions and hey presto auto wipers work as they should. This is the gel pad I bought of the bay. Thanks all for your inputs. Much appreciated 🙂

[normski2]

Ah nice one.

Well done you. 👍

[Mr Vlad]

🍻 m8