2002 Diesel Climate Control

Are you sure about the compressor not engaging when you turn on AC?

If you are then you likely have two issues maybe three.

Your issue with the control of the heat and possibly the AC not blowing cold is the blend door. It has likely failed. Did you have any foam blow out of your vents? That's the seal on the blend door blowing out.

Your issue with the control of the air flow is the mechanical switching attached to that dial, it likely broke inside the dash somewhere so when you turn the dial it actually doesn't turn anything.

If you clear up both those problems and still have no AC then you've also got a problem with your AC system, which may be as simple as more coolant being needed.

Thanks for the reply. The funny thing is it happened all at once. I had a death in the family and the car sat for about two weeks. The next time I used it nothing worked. I had noticed some foam at the vents from time to time. Before this time the AC compressor worked fine along with the heat and controls. If someone could steer me in the right direction on what I need to do to fix this I would be very thankful.

You should be able to find a DIY here on the Blend Door fix, and also the climate control knob I think has a DIY repair post somewhere here.