I have a 2005 Grand Caravan SXT and when I run either the defrosters or the A/C, the idle has a deep growl to it, which can dissipate or even stop if I turn of the A/C or change to vents instead of defrosters. Is this a sign that my compressor is going bad?

 

I would suspect the compressor or compressor clutch.

 

Does it go away when you rev up or is it just at idle.

 

Tizzy1, as you rev the engine or start driving the noise gets better.

 

usually a sign of something else causing the noise. Seem the extra load on the engine causes whatever it is to get louder.