1994 Pontiac Sunbird Amount of air from vents

1994 PONTIAC SUNBIRD
280,000 MILES • 4 CYL • FWD • AUTOMATIC
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PROFESSORCHAOS96
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The amount of vents coming from the vents in my car seems to be inadequate. When on the vent setting, the middle vent has plenty of air, however the two on the passenger side and the one on the drivers side is about 1/4 of that in terms of flow. The defrost vents don't seem to be putting out alot, either. The amount of heat is fine, and it transitions from hot to cold just fine as well. Another thing to note is when I set it from hot to cold, flow increases quite a bit. Are these cars known for blockages? Or is it the blower motor or actuator? OR, is this normal for these cars? Any help would be appreciated, thanks!
Dec 16, 2009 at 4:28 PM
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JACOBANDNICKOLAS
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It isn't normal. Actually, if it works normal on AC but not heat, my guess is the heater / ac vacuum actuator isn't working or there is a vacuum leak causing the system to not function properly. Here are schematics of both the vacuum system and the HVAC system. Check for proper vacuum the both actuators (vacuum schematic) and make sure the mode valve shaft is working (HVAC schematic).


https://www.2carpros.com/forum/automotive_pictures/249084_vent_1.jpg


https://www.2carpros.com/forum/automotive_pictures/249084_actuator_2.jpg

You will most likely need to enlarge the pictures. Let me know what you find and thanks for using 2carpros.com. Joe
Dec 19, 2009 at 12:10 AM
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PROFESSORCHAOS96
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Appreciate the response Joe. The pictures won't enlarge, and if I stretch them I can't pick it out. Is there any way to send over a link, or perhaps email them to me? It's [email protected] Thanks for the help!
Dec 19, 2009 at 11:40 AM
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JACOBANDNICKOLAS
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I was afraid of that. I will try to send it to your email. Keep your fingers crossed.

Joe
Dec 19, 2009 at 5:19 PM
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PROFESSORCHAOS96
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It worked, thanks for the photos Joe; one question though, where are the exact location of the actuators? Are they just on the back of the in dash unit? Because what I gathered from your first post is, airflow should be the same whether it's on the hot or cold setting. I'm thinking the heat/defrost or the A/C-heat actuator may be bad. Or, is there any chance there would be any leaves or something in front of the heater core? Because the air has to flow through it before it gets to the interior. Thank you again Joe, appreciated the responses.
Dec 19, 2009 at 8:38 PM
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JACOBANDNICKOLAS
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I'm gd to help, and really glad you got my email. I can never get it to work, but my 12 year old son had to show me how to use it. With all the computers in cars anymore, and nearly 30 years of working on them, one would think I would have no trouble, but...

Yes, they are on the inside. If there was a blockage of leaves, I think you would smell something from it but that isn't impossible. The first one I would check is the heater / defroster. It could limit the air flow.

Let me know what you find, and thanks for using 2carpros.com.

Joe
Dec 20, 2009 at 11:54 PM
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PROFESSORCHAOS96
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I was having some radiator troubles, so I replaced mine with a new aluminum core rad last night, as well as some better coolant (and a complete flush, of course) and the air temperature at the vents now is awesome, you can barely hold your hand to it. I'm surprised the radiator made that much of a difference. I'm going to get my hands on an actuator when I get the time and hopefully get a bit more airflow. Thanks for your time Joe, Merry Christmas!
Dec 22, 2009 at 7:03 PM
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JACOBANDNICKOLAS
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I'm glad it's fixed! Thanks for the positive feedback. It may sound crazy, but it makes me feel good to have helped someone.

Thanks for using 2carpros.com, and I wish you and your family a great Christmas!

Joe
Dec 22, 2009 at 8:11 PM