I think my a/c compressor went. When you look at the motor from the passenger side its the farthest pully towards the front of the engine at the bottom. When I turn a/c on smoke comes out of the pully, turn it off smoke stops. Can just the a/c clutch be replaced by it self , or do you have to replace the entire unit. Also any estimates on what this mite cost? Does this effect the defoger?