On my '05 XF I have a loose fan switch shaft than jumps fan speed due to shaft looseness! I ordered new potentiometer to replace the old one. Haven't removed AC control head yet as it seems to be a big task. Don't know if this will cure my problem but guess I'll find out. If you need new fan speed switch I got mine from Digikey.com. They are cheap so I bought three for two spares.