C-3, rear Astro Ventilation actuator

[D S.]

1970 Corvette convertible. A friend has this question:
The astro ventilation has an actuator back by the the rear deck vents. The flaps were stuck shut when I got the car. I pulled them down and now with the vacuum reconnected, I cannot get them to close. I blow/suck in to the actuator and it appears to work. I checked for crimps and obvious blockages and could find nothing obvious. Do you have any ideas on what else to look at? It appears that I am not getting any vacuum back there at all.

Thanks,
Scott

[Michael W.]

Re: C-3, rear Astro Ventilation actuator

The vacuum source is from the heater control panel on the center console. When the temp control wheel is moved away from full cold (or close), the multi selector valve underneath sends vacuum to the line that leads to the actuator under the rear deck.

In other words, the flaps should close as soon as you ask for heat.

It was -3F in Montreal yesterday, my flaps were fully closed I can assure you.

[Michael W.]

Re: C-3, rear Astro Ventilation actuator

The vacuum source is from the heater control panel on the center console. When the temp control wheel is moved away from full cold (or close), the multi selector valve underneath sends vacuum to the line that leads to the actuator under the rear deck.

In other words, the flaps should close as soon as you ask for heat.

It was -3F in Montreal yesterday, my flaps were fully closed I can assure you.

[D S.]

Re: C-3, rear Astro Ventilation actuator

Thanks, Mike. By your temperature standards our weather here in Texas is pleasant then. It's 47 and cold rain, tomorrow 44 and 20-30 mph winds. Our lows of 28 are probably not even your highs.

Scott

[D S.]

Re: C-3, rear Astro Ventilation actuator

Thanks, Mike. By your temperature standards our weather here in Texas is pleasant then. It's 47 and cold rain, tomorrow 44 and 20-30 mph winds. Our lows of 28 are probably not even your highs.

Scott

[Greg L.]

Re: C-3, rear Astro Ventilation actuator

-3F eh? ....well I guess I shouldn't complain then because it's 32f out here in Calgary.

Scott, does the rest of the heater controls/doors seem to work? If they work then you are obviously getting vacuum to the selector valves....sorry but I don't know for sure which one closes the rear vents.

Anyways, if these controls work then you might try checking the vacuum tube that runs down the passenger side of the driveshaft tunnel near the top. The one on my 69 was starting to rust away from the T-Tops leaking onto the carpet so I would think that if your buddies was corroded too bad then that might be the source of the vacuum leak. It should be easy enough to check out once the parking brake console is removed.

[Greg L.]

Re: C-3, rear Astro Ventilation actuator

-3F eh? ....well I guess I shouldn't complain then because it's 32f out here in Calgary.

Scott, does the rest of the heater controls/doors seem to work? If they work then you are obviously getting vacuum to the selector valves....sorry but I don't know for sure which one closes the rear vents.

Anyways, if these controls work then you might try checking the vacuum tube that runs down the passenger side of the driveshaft tunnel near the top. The one on my 69 was starting to rust away from the T-Tops leaking onto the carpet so I would think that if your buddies was corroded too bad then that might be the source of the vacuum leak. It should be easy enough to check out once the parking brake console is removed.

[D S.]

Re: C-3, rear Astro Ventilation actuator

Thanks, Greg. All these great suggestions will certainly help pinpoint the actuator problem.
Our average winter temperature in this part of Texas is in the 50s so I can't complain. Heck, my tomato plants are still thriving. And it's not unusual to see tops down on convertibles in winter here.

[D S.]

Re: C-3, rear Astro Ventilation actuator

Thanks, Greg. All these great suggestions will certainly help pinpoint the actuator problem.
Our average winter temperature in this part of Texas is in the 50s so I can't complain. Heck, my tomato plants are still thriving. And it's not unusual to see tops down on convertibles in winter here.