Wipers don't work on rain sensor, 2001 X5

[Speed addicted]

The wipers on my 2001 X5 stopped working on the rain sensor tonight, they worked on slow and fast wipe but would wipe about 4 times then park 2" from the bottom of the screen on rain sensor.
This happened after driving from Glasgow to Aberdeen in heavy rain with the rain sensor on all the time, when the rain got lighter and the wipers went intermittent they just stopped completely.
They seem to have fixed themselves as I pulled into the drive, any idea where the relays are? Could it be water ingress?

I've just spent a grand on the front suspension, please let this be simple!

[TheEnd]

try cleaning the windscreen first, up by the rear view mirror is a little square window where the sensor sits

http://www.bmw.com/com/en/insights/technology/tech...

You may have have a moth stuck to it.

[trs998]

Mine get cranky from time to time, and the answer is invariably to pull over and get a bit of paper and give the little window on the windscreen above the inside rear view mirror a quick scrub - it works by sending an infrared beam at the inside of the glass, for two diagonal bounces. If there's water on the outside, then that has a different refractive index to air and more of the infrared is lost. The amount of infrared that comes back into the sensor is then compared to the sensitivity setting on the stalk.

I second TheEnd - probably fly brains on the glass on the top of the sensor.

('01 E39 - probably same sensor)

[Speed addicted]

Well I've given it a good clean, and now it's not raining so I tested with a jug of water and all appears to be well!

Thanks for the replies, it's nice when the fix is just cleaning.