REleew

Completely rebuilt the A/C on the 77 Vette.... Questions:

Should the A/C - Heater Core door be fully shut with the Climate control set to the Extreme Cool position?

If yes, there is a bounce back created by the bypass switch mounted on the internal passenger side duct. I have replaced the switch and there is still a return on the cable even after adjustment creating the door to be about 1 inch open. Not completely closing off the Heater Core!

Even with my Heater Core Shut off with valves at the pump I want to get optimal cooling by completely closing off the core. Should the door be fully closed???? What am I missing!

Thanks in advance for any help!

79vetter

I know exactly what you are talking about and have the same issue - not sure if it is normal or not. I would think that the door would be 100% closed when the AC is on.

REleew

Same Here...... Makes no sense! Do you know the function of the switch? I have everything apart so I can depress it. When I do... I DO NOT see anything changing position.

minitech

If you open the hood and go to the airbox at th passenger firewall there is a resistor block panel that is right on top of the box held in with two screws. Looks kind of shaped like a water flange gasket shaped panel. Take that out and you can look into the box and looking in you will see the door that blends the hot and cold air and it moves when you move that lever back and forth.

On mine the door stays open a little when on all cool, not sure but it might be that way standard. I put a valve on the heater hose though so the core does not get hot and it doesn't matter.

REleew

Understood.... Did that. Just trying to understand why there is a 1" opening to the heater core select when trying to optimize AC air over the coil.

minitech

Mine had about 3/8 inch opening when optimized.