Does it work from the switch on the back of the centre console ?
If it does most likely just crudded contacts in the front switch, if not need to check for power at the motor etc, could be break in wire from body to door etc, or a duff motor.
Chances are a duff front switch, the contacts have the smallest blob of silver you have seen on them, so take apart and clean up.
You could also add one touch whilst there, so much nicer!!
tabetha