I have an A4 1.9 Diesel and for some time have had erratic problems with the windscreen washer and wipers.
The windscreen washer (Pull stalk back) only works about 10% of the time, usually no washer motor activates and no movement of the wipers. Sometimes the single wipe (Stalk push down) doesn't work, sometimes the intermittent wipe (Stalk one click up) works as single speed wipe or sometimes not at all, sometimes single speed wipe (Stalk two clicks up) acts as double speed wipe, it really is all over the place. My local garage have looked at it but say that they can't tell if it is the stalk or the ECU and it is expensive to replace either to only find out it doesn't cure the fault.
Has anyone come across a similar problem and does the wiper system have its own ECU or would it be controlled by the main engine ECU?