I had a similar issue with my wipers auto function, and I read something somewhere, cant remember where, was 2 years ago now, that said you do the following to turn them on and off (it worked for me)
Pull the wiper down to the first notch, back to off again and then back down to first notch again, with approx half a second between each state.
Seemed to work for me, I know because I often pull it down and up again quickly to wipe the windows forgetting it was already on and turn it off by mistalke.
I could be completely wrong, and it may be mine always worked, but seems their is on mine anyway an on off function
Just like the auto locking doors, on theVolvo I used to have you had to have Volvo programme them to be on or off, but in the lag, if you hold the button next to the hazzard light switch down it will turn on or off the lock feature.