[RVasq10]

I have an 80 Caprice with a rebuilt 350 motor. I recently had the A/C and heating systems replaced and have an issue with switching between A/C and Heat. I purchased a bench test refurnished control panel and having same issue still. I have it set currently to A/C but I can’t control switch to heat using the panel on car. I have to manually open up dash and close the door so heat from engine can flow in. I have checked all vacuum hoses and doesn’t hear or see any leaks. Any ideas what it could be? Also some photos of what I’m dealing with. Thanks for any help.

 

[Brhatweed]

There's a servo in the box located to the left side of the blend arm you're moving to control the temp that normally moves the rod, this box is basically the brain of the auto climate control. Check the integrity of the mechanism and if its intact move the temperature dial up and down with the system in Auto and see if the servo motor is moving the arm.