What year car is it and passenger or drivers side along with extras like electric folding mirrors etc
VW changed the module in 2007 and later ones are not compatible with older ones as they also decided to change the pinouts
Be warned you are looking at around £200 from the dealer
You need to take the interior door panel off and its fitted with 3 bolts, 10 min job to change once the door panel is off
Its the white part in the centre of the door