I did a search, but nothing really turned up. So here's the problem: Even when the heats not on, the blower motor's off, and the engine's warmed up, there's a constant flow of hot air coming out of the vents under the dash. And when the heater and blower are actually turned on, it acts like it would normally. This the first summer I've had with the car so I guess I never noticed this before because whenever I was in the car this winter, the heat was usually on anyway. But now that spring is finally here, it's gotten a lot more noticable. How do I fix this? If I had to guess, I'd say a vent is stuck open somewhere. Any help or advice would be appreciated.

 

Anyone?

 

Ive got the same problem with mine, but the hot air comes out about the dash and hits the windshield causing it to fog up. Wish i knew what the problem was.

 

More than likely a vacuum leak somewhere causing the vents to not close fully. My 87 Grand Prix did it, and my 85 Trans Am does it. The vents just don't close when the blower is off, and air finds it's way in.

 

my 91 bird did it, my 87 camaro did it, and my 84 TA did it...my TA didn't have any of the AC or heating elements under the hood. Buy the coolant hoses were still routed through the heater core. So I went ahead and pulled the heater core. no more heat coming through.