mk3 has an 's'-contact, this becomes actives after the key has been inserted and the ignition being turned on but remains on until the key has been removed again. this is how its on my 96 model.... on my 94 the same contact was active as soon as you put the key in....
s contact wire is brown/red... among other things goes to your radio. you can use it to power a relay for window operation. would not draw that much current from it directly.