'99 328 Windscreen Wipers Intermittently Cutting Out

Hi,

I have a 1999 BMW 328 Saloon (in the United Kingdom) and recently, I've had
a strange problem with the windscreen wiper and windscreen washer
intermittently cutting out for no apparent reason.

This has only happened twice, but the first time was on a motorway in heavy
rain, which was quite frightening.

Basically, I am driving along, with the windscreen wipers on, and suddenyl
without warning, they return to the "off" position on the windscreen, and
stay there. If I try moving the column to any of the windscreen wiper
settings, or pull it towards me for the washer fluid, then nothing happens.
And then suddenly, it all starts working again. The first time, it stopped
working for about 5 minutes, the second (about three weeks later) it stopped
for about 30 seconds.

I have a rain sensor, and recently had the windscreen replaced because of a
crack - could this be related in some way?

If anyone has any idea what might be causing this, then I'd be very
interested to know.

Thanks,
Darren.