Rain Sensor Windscreen Wipers have a mind of their own!

[The Mechanic]

I have a 2012 E70 30d MSport.  The rain sensor wipers seem to have developed a mind of their own.  As an example, on the way to work today it was light rain and I was in heavy traffic doing less than 5 mph but the wipers were on full speed.  The only way I could get them to slow sown was to turn the sensitivity right down.  This has been happening now for a few days.  Anyone had this problem or suggest a cause/remedy?  Car is in warranty.

[mswiatk70]

Perhaps coincidental, but my previous X3 did that regularly up until I had the windscreen changed to a genuine OEM glass. Perhaps the change of sensor (which came with the new screen), and or new glass combination removed the faulty part. If you've had a non OE screen fitted, that 'might' be the cause, although I assume many report no issues in doing so. In any case, as you're still in warranty you should be able to get this resolved without issue. Best of luck.

[X5Sport]

Check the clarity of the sensor window behind the mirror housing (looks blue/purple) and must be clear.  If it is in any way opaque, or like mine has a dead spider in it, it could affect the system as it reflects an infra red beam off the screen to determine the refraction level.  Anything obstructing the beam return signal can throw the controller into a sulk!

Richard

[The Mechanic]

Thanks guys, will check the sensor.  The screen is original BTW.