01 s80 2.9 non turbo have changed cabin air filter and evaporator temp sensor. Air is ice cold coming out of ducks. But air flow is not hard enough to cool car. You can cut the air off and the fan will speed up 50% faster. With air on you can push recirculiate button in and it will make no difference any thought on this

 

I'm no expert, but this seems like it may be the blower motor. Do you notice a significant difference between the lowest setting and the 2nd setting? From very low, to what you would normally consider low.....it's hard to explain, but the general symptom sounds like the blower motor.