I have a 2005 Mazda MVP, and the rear is blowing hot air, even when AC is on. The AC works great in the front. I've called the local dealership, and they want to do an "AC Diagnostic" for $175. Before we do that, I'd like to rule out obvious problems like a bad switch. Are there any easily accessible switches/actuators that can easily be tested before doing the whole AC diagnostic?

 

I have a 2000 MPV van and I was wondering about the rear air as well. It turns out that at least in my model the rear vents are not connected to the AC system at all. They do get heat but not AC. You should check your owners manual to see if this is also true with your later model. Probably is.

 

Interesting ... will do.