hey guys i just got a 77 Vette. and i the air from the A/C only comes out through the bottom vents when it is cooling. I know it is a vacuum ordeal but has anybody experienced this so they can lead me in a faster direction! Thanks dudes
There is a vacuum actuator for the air door that directs the air to the upper vents. This is a vacuum/electric diagram of a 68 HVAC setup. Your should be very similar. Sounds like a disconnected vacuum line to me (or a bad actuator). You might have to prit this to really see.
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Manuel, The actuator that is in the plenum is not visible unless the front clip is removed. You may see a vacuum line going down to it from the wiper well. This actuator switches between closed cabin mode (air from inside the car is re-cooled) and fresh air mode where outside air is cooled. The actuator in the kick panel works in conjunction with the plenum actuator. They are both connected into the same line with a T connector. The kick vent is normally closed (by a spring) and the plenum actuator is normally open.Hi there, I have a similar problem on a 68 coupe if I can ask a quistion here about it? In hooking up the vac. line and looking at this diagram, it shows a actuator in the plunum, yea cool where is that? I took the heater box out and nothing and see nothing in where the cooling air comes in. I see the one actuator in the kick pannel only, is the another one I don't see on my car? And it is a 68 coupe with air. Thanks so much if you can help. Manuel
Manuel, The actuator that is in the plenum is not visible unless the front clip is removed. You may see a vacuum line going down to it from the wiper well. This actuator switches between closed cabin mode (air from inside the car is re-cooled) and fresh air mode where outside air is cooled. The actuator in the kick panel works in conjunction with the plenum actuator. They are both connected into the same line with a T connector. The kick vent is normally closed (by a spring) and the plenum actuator is normally open.
It seems like a complicated system but it all makes sense when you take a look at it.
YES, you can look down in there with a flashlight, and you will see 2-3 5/16 hex bolts on a small metal bracket, that door is removeable, , actuator and all...hard to get to....sometimes the rubber sealer material gets awful tired and cracks/falls off....I had the actuator fail some years ago on my '72 here where I had to pull the entire door mechanism to get to it.....I just sealed it all off permanently, and pulled the inner door off, eliminating the vac line....permanent recirc for my car....being as it's a convertible....I got plenty of fresh air.....Thank you for the info! The hose is off on my car as it is just going back together after a frame off. But I didn't have the front clip off the body and I don't remeber this hose being attached anywhere. I wanted to be sure I had all the mechincal done before finishing my body work. Is there a way to get to this actuator that you know of without taking the fenders off? Again thanks for the help!! Manuel
Good possibility you have a vacuum leak somewhere in the main feed or early on in the system. When there is no vacuum, the system defaults to the heat position (figures with a car designed in Detroit).hey guys i just got a 77 Vette. and i the air from the A/C only comes out through the bottom vents when it is cooling. I know it is a vacuum ordeal but has anybody experienced this so they can lead me in a faster direction! Thanks dudes
Probably not. There's a special in-line high current fuse for the high speed setting on the fan. If I recall correctly, it's a 30A fuse. It's either located on the heater core box or on the firewall (its been a couple of decades since I had to replace one, so forgive the lack of detail!).so this is off topic, somewhat but w.e... my A/C fan only blows air in all the settings except HI. is the switch shot?
On a 79 it would be a fusable link between the starter and the high speed blower relay.location any1?????????????