Has anyone installed a manual fresh air vent to by pass the regluar AC system and vent system, I have replaced control inside cabin and still blow warm air thru vents, i have closed off the coolant line with a ball valve still warm air any advise would be great
thanks

 

Well, I've had the ductwork apart to test the actuators so have some idea on how it works. Its all interconnected so how were you able to isolate ducts from the kick panel area to the dash vents to bring in fresh air?

I never found outside air cool enough to cool the cabin...way too much heat generated by the big window and heat emitted from underneath thru the tranny tunnel.

 

Have an automotive AC shop test your stock system. Cool air might return with something as simple as a charge of freon.

For AC cars, fresh air can enter the cabin only at the passenger's vent in the footwell. All other vents are sealed. You can disconnect the vacuum actuator to the vent and manually open the door, but you are likely to be unhappy with the air flow.

 

Noticed that I also had limited air flow into the cabin when using either the vent or A/C position. I disconnected the fresh air door vacuum actuator by removing the blower motor resistor coil assembly on the heater box and reaching inside to manually open the door. Now
I've got about 50% more air flow than I had before and I love it. My '79 doesn't see cold weather and I use a manual heater shut off valve.

 

I found that the fresh air coming through the fresh air vent that Mr. Easy Mike is speaking of was being SUPERHEATED by my sidemount headers before coming into the cabin. Even after I bypassed the heater core (which I've subsequently disconnected because of a leak), I was getting a MASSIVE heat load through that one vent.

It was so hot my wife couldn't even keep her feet in the passenger footwell. Great in the winter. Stinks when it is over 85 degrees.

Last time I had my car apart, I simply removed the vacuum hose that leads to that vent. Plugged the hose with a very precisely sized nail.

Now, I get the "regular" heat from the dash, windshield, and center console/tunnel area, but no "active" hot air being furnace blast into the cabin.

It was 92 degrees outside today and I've been running around with the T-Tops ON, long black pants on, and a rolled-up long sleeve shirt (business casual), and I was hot but not uncomfortable.

Take the T-Tops off and I think I'd be even better. In shorts, I'd be downright comfortable.

Pull the passenger kick panel (you'll need to remove the sill plate to get it off) and disconnect that vacuum hose. You'll notice a HUGE difference.