I have a 2003 with auto climate and whenever the A/C is on fan setting 3 or 4 it makes a loud noise that can be heard over the frankencar, but as soon as its turned down it goes away. Its not like a hissing or ticking noise like some have experienced, more like a deep motor noise. My only guess is that there is a design problem with the fan. Sounds like the tips of the blades are going supersonic similiar to what can happen on the prop of a an airplane. Has anyone else experienced this?

 

I have not noticed that problem with my 2003 so it may just be in the assembly of your car or a motor problem. Does it only happen with A/C or with heat as well?

 

me too, I hear the same thing