I would go in two steps: replace the blower regulator first (or the whole blower if you can get a used one in nice condition, like on Ebay from a Florida car). Then see how it goes and eventually replace the small cabin thermistor. Some people recommend to have the key in POS II whenever the batter...

Thank you for the reply oragex.

I'll try that and see if it works.

Hello folks, I have a 06 S60. Everytime I get in out of the car, I have to put the fuse in when getting in the car and out. When I plug the fuse in, the fan only runs at full speed and cannot reduce the speed at all. When turning the fan speed knob, the lights change from low to high and high to low...