1980 Missing Air Flow for Heater-A/C
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Heel & Toe
Joined: Sep 2023
Posts: 19
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From: New Jersey (Ask me what exit :)
1980 Missing Air Flow for Heater-A/C
1980 base coupe automatic, 350 L48, air conditioning
There is no air flow into the interior. The blower motor is spinning and works at all speeds. All the vacuum actuators have been confirmed to be working properly. The temp control slide switch moves the temp door inside the heater box properly but there is no airflow into the car. I pulled out the blower motor resister and looked down inside that compartment. All looks reasonably clean and functional. Even on high speed there is no air blowing out this hole and I think there should be. Where can I look next??? What is the path the air takes from the blower motor to the output side of the a/c evaporator?
There is no air flow into the interior. The blower motor is spinning and works at all speeds. All the vacuum actuators have been confirmed to be working properly. The temp control slide switch moves the temp door inside the heater box properly but there is no airflow into the car. I pulled out the blower motor resister and looked down inside that compartment. All looks reasonably clean and functional. Even on high speed there is no air blowing out this hole and I think there should be. Where can I look next??? What is the path the air takes from the blower motor to the output side of the a/c evaporator?
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If the blower motor is spinning the squirrel cage. I'd have to assume the heater core is completely blocked by debris. Leaves and such over the years. No screen or filter to block this.
separate the heater core box and clean out all the debris. Something is blocking airflow. And this would be the logical course of action.
separate the heater core box and clean out all the debris. Something is blocking airflow. And this would be the logical course of action.
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Heel & Toe
Joined: Sep 2023
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From: New Jersey (Ask me what exit :)
Thank you, 4-vettes. I thought about that. I can actually see inside the heater box and view the heater core through the hole where the blower motor resister lives. There doesn't seem to be anything in there. I see the temp door move from end to end when the temperature slide switch is positioned from hot to cold and back again. What I can't see is the space between the blower motor and the A/C evaporator. It appears to me that the air flows into the squirrel cage from the inside or outside (depending on switch positioning). Then the first place it goes it across the A/C evap. Thats the area I cannot see. I really don't want to take out the A/C evaporator core (looks similar to the heater core) unless it's absolutely necessary. (R12 refrigerant is not easy to find these days.) I'm thinking the next step is to remove the blower motor and maybe see inside (using mirrors). That motor needs replacing anyway.
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Joined: Aug 2021
Posts: 58
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From: Knoxville TN
I had a similar problem on my 75.I dunno if the 80 routes air like the 75 but heres how I addressed my issue.
I pulled the blower motor and used a light & mirror to look towards the AC evaporator and couldn't see it due to the leaves and debris covering it. I removed the resistor which gave me some limited access to the other side of the evaporator. Using a long wand airgun, I inserted it through the resistor hole aimed towards the evaporator and a wet/dry vaccum hose stuffed through the blower motor hole I proceeded to suck & blow that evaporator clean. Also had to vacuum out the void in the fender which is the intake air plenum. I stopped when I no longer saw dust getting blown out and/or around that entire duct system. Yep, 47 years of debris got removed from the Vette that long day.
I now have air flow through all registers when selected. The air flow isn't as powerful as modern vehicles but I can feel it especially on high setting. I'm guessing theres some more clogs down in the heater core and/or duct work but it's sufficient now and the heat & defroster will run me out. I'm slowly getting motivated enough to get the AC working, well almost, LOL.
Good luck
I pulled the blower motor and used a light & mirror to look towards the AC evaporator and couldn't see it due to the leaves and debris covering it. I removed the resistor which gave me some limited access to the other side of the evaporator. Using a long wand airgun, I inserted it through the resistor hole aimed towards the evaporator and a wet/dry vaccum hose stuffed through the blower motor hole I proceeded to suck & blow that evaporator clean. Also had to vacuum out the void in the fender which is the intake air plenum. I stopped when I no longer saw dust getting blown out and/or around that entire duct system. Yep, 47 years of debris got removed from the Vette that long day.
I now have air flow through all registers when selected. The air flow isn't as powerful as modern vehicles but I can feel it especially on high setting. I'm guessing theres some more clogs down in the heater core and/or duct work but it's sufficient now and the heat & defroster will run me out. I'm slowly getting motivated enough to get the AC working, well almost, LOL.
Good luck
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Heel & Toe
Joined: Sep 2023
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From: New Jersey (Ask me what exit :)
Issue resolved!
I followed Volfandt's direction and removed the blower motor. OMG!!! The blower motor/squirrel cage chamber was packed with mouse nest that ran down into the A/C evaporator compartment. It was so packed I had to use a screwdriver to start breaking it free. Using the motor box and the intake air vent, I was able to get it out by snaking a vac hose into it and sucking out all the debris. You would not believe how much "stuff" was packed between the squirrel cage and the A/C evaporator. I actually had to stop and empty my shop vac halfway through. Compressed air blown into the opening for the blower resistor finished getting all the crap out. This car sat for 20 years and the critters lived there in style.
No more nests and now I have air flow, wonderful air flow.
Thanks to 4-vettes and Volfandt for their guidance
I followed Volfandt's direction and removed the blower motor. OMG!!! The blower motor/squirrel cage chamber was packed with mouse nest that ran down into the A/C evaporator compartment. It was so packed I had to use a screwdriver to start breaking it free. Using the motor box and the intake air vent, I was able to get it out by snaking a vac hose into it and sucking out all the debris. You would not believe how much "stuff" was packed between the squirrel cage and the A/C evaporator. I actually had to stop and empty my shop vac halfway through. Compressed air blown into the opening for the blower resistor finished getting all the crap out. This car sat for 20 years and the critters lived there in style.
No more nests and now I have air flow, wonderful air flow.
Thanks to 4-vettes and Volfandt for their guidance
