On a 2004 Chrysler Sebring, the air only works when turned up to maximum power. At any of the 3 levels below that, no air comes out.
Additionally, when the heat is on, it only blows hot air while the engine is revving. When I release the gas, I can start to feel the air gradually cool down (especially at stop lights). This was not much fun in the winter - I haven't tested yet to see if the AC works the same way now that it's warm out.
What could be causing this, and would the parts be expensive and labor time-consuming?