AC blowing air from under dash with AC off?

[Rotech]

my car was not running for a while when I purchased it from previous owner. Today while running it I noticed that hot air (today's was a very hot day) was blowing from the floor vent underneath the dash with the AC selector off. Has anyone experimented something like this before? Currently my AC isn't functioning.

I had the blower positioned to low, but the AC was off.....

 

[SoFloG]

You haven't owned an 80s GM vehicle of you've never experienced it. Iirc it has to do with the vacuum acuumulators(balls) in the engine compartment, or vac lines running to and fro. Quick solution is some a/c ducting tape...

 

[Rotech]

You haven't owned an 80s GM vehicle of you've never experienced it. Iirc it has to do with the vacuum acuumulators(balls) in the engine compartment, or vac lines running to and fro. Quick solution is some a/c ducting tape...

How do I identify the vacuum acumulater? How can I trouble shoot it?

 

[Rotech]

I have located the the vac ball, there 2 connections on it. One comes from the manifold (black) to the ball and the other is purple that comes out of the ball to the interior of car. I checked the black hose and it seam sucking air ok. I removed the purple and checked suction from ball,but it was not quit as powerful as from the source hose.

 

[Texas82GP]

Check the ball for cracks. See if it is leaking vacuum. New ones are available from Rock Auto.

 

[pontiacgp]

my GP doesn't have a vacuum reservoir, the pink line goes directly to manifold vacuum. I'm not sure that is the way it came from factory but that is the way it was when I bought the car and the system seems to work fine. These cars never turn the fan off either so the air circulates constantly. I'm not sure how much air is coming out of the vents and it might just be a problem with the heater control.

 

[Texas82GP]

When the air is coming out of the floor vents what mode do you have the HVAC control set to?

 

[Rotech]

When the air is coming out of the floor vents what mode do you have the HVAC control set to?

It is set to off and the fan to low.... (I don't have the car in front of me) In other words all levers switched to the left. Is that the way the AC should be turned off?

 

[Texas82GP]

It is set to off and the fan to low.... (I don't have the car in front of me) In other words all levers switched to the left. Is that the way the AC should be turned off?

Yes, all the way to the left is off. I don't think it is unusual to have air coming out of the floor vents when the system is turned off. Hopefully others will chime in. My car hasn't run in a few years so I'm not certain but that's the way I remember those cars behaving.

 

[jeremyandthemonte]

Air will always come out my sunfire does it my brothers brand new truck does it. I think it is just a safety future to keep the air clean inside the car