Technical Uno Mk2 windscreen wiper - only high speed working

[eby]

Uno Mk2 Diesel. The windscreen wiper slow and intermittent speed are not working at all, only the high speed (position 3) is working. And when switching to position 2 or 1 from highspeed, the wiper stops at its position. However when switching to position 0 (off), it returns to its resting position.

How to diagnose this, Is there a relay for wiper motor ?.

Thanks,