I doubt the switch is bad, rather you are low on freon. check for bubbles in the receiver/dryer glass. If you have them you need freon.
2005 320 CDI
2006.5 VW Jetta TDI
1991 560SEL (179000 Sold)
1972 280SEL 4.5 ('The Lead Sled' 320000 miles when sold.)
1972 220D (225000 when sold)