Rain Sensor

[malc1950]

Hi all i removed my rain sensor from the windscreen as air bubbles appeared between the screen and the sensor and the auto wipers stopped working,
after cleaning the glue off the screen and the sensor i then held the sensor up to the screen and activated the auto wipers sprayed the screen with water
but the wipers still don't work, they only gave one wipe when i offered the sensor to the screen could it be that the car is not being driven,

[X5Sport]

Sounds like the same issue I had. Unless the sensor is bonded to the screen correctly - with no air gaps - it won't work. In 'Auto' mine gave just one wipe and that was all. The wipers worked in the other settings, as did the washers. The auto wipe system works even when stationary.

There is supposed to be a way of fixing it with optically clear silicone but I've never tried it. In my case it was a new screen required. Have you got glass insurance?

[malc1950]

Hi XX5 yes i have been doing my home work and there are people that have managed to stick the sensor back on the screen and the sensor works ok,
but like you said the correct glue must be used, i have bought the clear glue they recommend, but first i want to test the sensor ,as i mentioned when i hold it to the screen and spray on water it gives only one wipe, i will have to get a friend to hold it to the screen while i drive to see if it works then ,

[X5Sport]

It might be being fooled by the air gap. Even a small gap will cause a change in the refraction index and it might just be enough to stop it working, these things can be finnicky - as you are finding!

Not sure what else to suggest to improve the bond but without actually glueing it so that you can check it before committing to the glue. I don't think the sensor is waterproof so you can't try a thin water film between it and the glass. Other things might contaminate the surfaces and prevent the glue working once you know all is well. But the symptoms are exactly as you would see when the sensor was not getting the right information (as is caused by an air gap as one problem, or a bad sensor as another).

Can you try another sensor?

[dirtymonkey29]

I had bubbles in mine, worked ok in daylight but not in the dark. All fine now after a broken screen was replaced

[malc1950]

Well i have the correct glue so what the hell !! weekend i will stick it back on, after i have looked at my friends BMW for the exact position of his sensor as i never marked my screen when i removed it, will let you know the outcome, Thanks all,

[X5Sport]

BTW what is the correct glue, and where did you get it from?

[malc1950]

The glue that was used on a e46 fix was "permatex clear rtv silicon 66b" the glue i have is "geocel aquarin sealent",
i have tested the glue that i have by trapping the glue between two pieces of cling film till it goes off and its as transparent as the permatex glue so it should be ok,will give a go at the weekend,

[malc1950]

Yesterday i re stuck my rain sensor back onto my screen using" Geocel Aquaria Sealent then left it overnight to dry pluged it in this morning , sprayed water on to test it in Auto and i have Auto wipers once again 

when i first removed the sensor and cleaned it off i tried holding it to the screen to test it but it wouldn't work
but once bonded to screen it works ok 

[pvr]

Excellent result and that for the price of a bit of glue 

[Johnny chimpo]

Malc, where did you get the Geocel Aquaria Sealent from?

[malc1950]

i got the sealent off ebay , i am in Manchester if you are local you can use mine  O:-)

[jaynana]

excellent stuff! this should come in handy at some point - cos although mine works i do have air bubbles.

btw, something i've kind of noticed - if its raining when i start the car the auto-wiper doesn't seem to start. a slight nudge with changing the sensitivity setting and off it goes, after that it works fine, self regulating itself.. is that normal?

[dirtymonkey29]

Mine does same jaynana.  I assume it's normal

[pvr]

Yes, that is the way to switch it on.

On the E70, we have a nice new switch instead on the stalk