I have a 1.8 TDi sport 2006 the 4 square switches in front of the gear shift on mine have the 3rd from left as the rear window de-mister what are the 2 on the left for? I had a look at them as I want to put in an aux 3.5mm female socket for phone etc the 2 on the left are connected to wires the one on the right is blank. also is there a 3.5mm aux socket available for these or will I have to drill and put in a chassis fixing socket?