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HVAC Question on my 77



Having a little trouble or maybe i just don't understand the functions on the HVAC system and when some of the vacuum actuators are supposed to be closed or open. At what setting should the fresh air door vent be opened (the one in the pass kick panel)?

When it is in DEFROST, only the upper grill is throwing out air. When the HEATER is toggled the center dash vents and the lower dash vents are blowing..same for a/c controls. I would think at the VENT setting the fresh air door would open, and that is on the same line as the door to the fan out in the wiper cavity, shouldn't that close too?? Anyway its not in that setting, actually in all settings the door stays closed.

FYI I am doing a frame off restoration, all new vacuum hoses, new actuators. It seems to be mostly working, just curious on the pass kick fresh air door. Thanks.

6880 Mike

Well-known member
Jun 30, 2006
The Bluegrass State
1968 convertible; 1980 L-82
Order the assembly instruction manual (AIM). The AIM has a diagnostics page for the HVAC settings; which doors open when, etc. The AIM will also help with setting your door glasses and thousands of other items on your car.


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