Air Vent questions and gap?

GrantOv · Dec 14, 2024

I pulled my dash and was curious about a couple things -

1 - I first noticed that there was about 3/4 of an inch gap between main center air distribution and the defrost ducting. Not sure if there is an adjustment I should make or if there is something like gasketing that has shrunk over time?
2 - I'm not sure if my car used to have air conditioning. When I move my HVAC control to cool, the wire connection depresses this switch. Not sure what the result of it is. I don't have compressor parts in my engine bay so there may be only remnants left if there was air conditioning at some time.

Thanks for your thoughts,
Grant

Moderator73 · Dec 15, 2024

GrantOv said:
I pulled my dash and was curious about a couple things -

1 - I first noticed that there was about 3/4 of an inch gap between main center air distribution and the defrost ducting. Not sure if there is an adjustment I should make or if there is something like gasketing that has shrunk over time?
2 - I'm not sure if my car used to have air conditioning. When I move my HVAC control to cool, the wire connection depresses this switch. Not sure what the result of it is. I don't have compressor parts in my engine bay so there may be only remnants left if there was air conditioning at some time.

Thanks for your thoughts,
Grant

As for the first item...yeah it looks from your picture like your foam seal is shot/gone. Here's a pic of what should be there but this is out of mine and pretty well shot too. It's just some soft foam that you could make another one and attach with some spray adhesive.

On the second item, that's a vacuum switch to goes onto connect to your Heater Hose vacuum motor under your hood so when your temp control lever is properly positioned the heater hose valve opens or closes to allow hot water to your heater core. Here's a link to a replacement valve that gives some additional info. Yours looks good in the picture with the proper hoses connected to it,and if you had temp control before you're good to go.

https://www.kentuckymustang.com/a-c-heater-control-valve-vacuum-switch-assembly-1967-1973-acp.html

Doug's 73 Mach1 · Dec 15, 2024

The big box behind the dash is for cars with factory AC. On the fire wall on the engine side there should be two connections for the AC freon hoses near the heater hoses. The heater controls should also have AC related markings.

GrantOv · Dec 15, 2024

Thanks!

I'll look into getting some gasketing replacement. Good to know this is just common with age. There is a flap internal to this vent assembly (your pic) that has some foam that has disintegrated facing out. I'm not sure how important that is since it is facing outward and frankly not sure how to remove this or replace the flap.

I do get heat so I believe the switches are functional. I'll have to look closer at the AC remnant freon connections. My HVAC controls do show AC but wasn't sure if it was original or not. It looks like my car did have AC at one time but given my time in the vehicle usually has windows open so I can soak in the sound and breeze it isn't high on my list at the moment to install.