So I really cannot get the control to switch from defrost, to floor or any other settings. So not ideal.
Any help on the remedy and how expensive? Thanks SF mechanics.

This message has been edited. Last edited by: old rugged cross,

These are vacuum operated, and with no vacuum they default to defrost for safety. The vacuum line usually breaks from all of the heat cycles. The line is black plastic and fairly thin, maybe 3/16" diameter. The line comes from the passenger side of the intake manifold and goes through the firewall on the passenger side.

Find the break, and most times you can repair it with a small length of rubber hose. Simply plug each side of the break into the hose.

Thank you SB, that is a big help. Really appreciate it.

You may have one of the few Astro vans still on the road. They didn’t seem to age well.

Haha sourD, the Astro had quite a run and there are still many on the road. The 4.3 liter V6 is a great engine. Most went for well into the 200k + mileage range.

There was a good reason tens of thousands were and are being used as contractor vans. A solid well built rig.

Thank you Shifferbrains. You had it right. Vacuum lines were indeed the problem. Worked with my local shop and they were able to fix.

My mechanicing days are behind me for the most part. But knowing where the problem was and talking with my local shop was very helpful. I really appreciate all of you guys who provide valuable input when asked about these types of problems. I am surely one of thousands who have benefited from those of you willing to share your knowledge and experience. I am grateful.

Glad I could help, and the issue was easily repaired.