i had that fuse already blown out when i got my car 6 months ago and the car was running AC without it. it must be a real common occurence. good tip on changing the fuse for the coming A/C season.
the main sensor is on the thermostat housing and it has a blue base. if you pull the connector off, the fan should go on at high speed. the other sensor is by the A/C drier which you test by shorting across the terminals - this turns on the fan at low speed.
1993 300e-2.8 - gone now <sigh>
"Do not adjust your mind, it's reality that's malfunctioning"