Jetta wipers only work when the car is in motion, washers not working at all

[veedubb]

My 2007 Jetta TDI few weeks ago wipers stopped working only when the car is stopped, as soon as you take off the wipers start up again, the washer jets are not working at all, somone mentioned that it is possibly a fault in the windscreen rain sensor, the car was involded in a minor accident & was in repair shop only really noticed this after i picked it up from repairs, it may be just coincidence that it played around same time, so im not sure if its related to repair work or just a common fault as a mechanic told me that he had a golf a while ago & it did exactly the same thingif anyone can shed some light on how this can be rectified would be great cheers :cool