Dodgy Headlamp Wipers

My 940 wentworth headlamp wipers and washers on one side don't work. Seems very strange that both systems aren't working on one side. How do I go about checking and repairing them? Sean

headlight wiper 

Hi wiper moter has self park disc in it take apart carefully clean ,lube rebuild note self park position on disc will find motor will be slightly faster for several wipes of headlight then settle.