The Heater/AC fan on my 02 S-type 3.0 will not shut off. It seems to work fine as long as the Heater or AC is on (High to low) but when I turn it off, it sounds as if the fan goes to high with the vents close. It does go off when the ignition is switched off. My first guess was a bad relay. My owners manual show the fuses but ignores the relays. Can someone help me out. Thanks Billy