2004 Saab 9-3 climate control

You suspect right

How do I fix this

Not an easy job. On most modern cars the fan is easily accessible down through the pollen filter and in but i reckon you will have to have the whole dash board out. Give Saab a call and ask the question as i may be wrong.

before condmeming the fan you have to be sure, start your car as some vehicles fans will not run until the alternator is on and charging, switch the fan to full incacse you have a resistor problem and you should be able to feel something though the vents or hear the fan, if you can't hear the fan then check the fuse, this is fuse No.6 located inside the right hand side dash panel as you open the door. If you can hear the fan running but have very little coming through check the pollen filter it may be blocked or wet, if not i would suggest that the heater control motors or control unit is faulty and the vent flaps are not being operated if it has climate control or if not you have a simple cable or control knob broken.