Climate control
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Instructor
Joined: Feb 2015
Posts: 140
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From: Seabrook Texas
Climate control
I'm a bit new here to posting so sorry if this is a dupe or a silly question as i couldn't find this answered anywhere else. i own a 88 vett and its a blast but one minor issue as summer is approaching and getting warmer, not a problem for a lot of you buried in snow atm 
, my concern for my cold air is becoming greater. Now, my problem is that after about 3-5 minutes of driving, the car will just start blowing full heat and nothing i do will stop it. I've tested it when it's 68 up to 82 and no matter what setting i have the c68 climate control set to, it will blow heat. However, when the car first starts and is NOT warm, the car will blow out nice cold air. side note, even when the car is blasting hot air through the vents, I've opened the hood and could see the compressor going and the high and cold lines to the compressor are VERY cold and most of the time have condensation all around it. any expert or someone who could help me please chime in as i wish to have nice cold air flowing through the vents. No check engine light although don't know why there would be one. As far as I'm aware there are no obvious vacuum leaks
, my concern for my cold air is becoming greater. Now, my problem is that after about 3-5 minutes of driving, the car will just start blowing full heat and nothing i do will stop it. I've tested it when it's 68 up to 82 and no matter what setting i have the c68 climate control set to, it will blow heat. However, when the car first starts and is NOT warm, the car will blow out nice cold air. side note, even when the car is blasting hot air through the vents, I've opened the hood and could see the compressor going and the high and cold lines to the compressor are VERY cold and most of the time have condensation all around it. any expert or someone who could help me please chime in as i wish to have nice cold air flowing through the vents. No check engine light although don't know why there would be one. As far as I'm aware there are no obvious vacuum leaks
Last edited by Nicksvette; Feb 23, 2015 at 09:42 PM. Reason: forgot something
Race Director
Joined: May 2006
Posts: 10,691
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From: Phoenix Arizona
It sounds like you have a controller issue (the box on the firewall to the right of the accelerator pedal with all the different colored vacuum lines coming out of it). Or possibly the heater door. Both are under the dash.
Thread Starter
Instructor
Joined: Feb 2015
Posts: 140
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From: Seabrook Texas
don't know if this is the problem but i've circled where it looks like a missing connector would go
good lord this looks like a mess. Dear last owner, what did you do under the dash
Race Director
Joined: Apr 2002
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From: Anaheim CA
You might have a bad or disconnected vacuum check valve. It supplies vacuum to the HVAC system in the cabin. It also supplies vacuum to the cruise control, so check to see if that works. The vacuum check valve (about $4 at any auto parts store) is located next to the distributor on the driver's side:
Thread Starter
Instructor
Joined: Feb 2015
Posts: 140
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From: Seabrook Texas
You might have a bad or disconnected vacuum check valve. It supplies vacuum to the HVAC system in the cabin. It also supplies vacuum to the cruise control, so check to see if that works. The vacuum check valve (about $4 at any auto parts store) is located next to the distributor on the driver's side:
As far as I can see, it's connected and tight
Thread Starter
Instructor
Joined: Feb 2015
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From: Seabrook Texas
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Thread Starter
Instructor
Joined: Feb 2015
Posts: 140
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From: Seabrook Texas
i don't know if yours is just disconnected but mine connects to where the single side goes directly to the headers and the other two sides go, one to what i guess to be the interior (very very tiny little, almost coffee straw like tube) and the other over to the vaccuum ball/cruise control.
Race Director
Joined: Apr 2002
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From: Anaheim CA
i don't know if yours is just disconnected but mine connects to where the single side goes directly to the headers and the other two sides go, one to what i guess to be the interior (very very tiny little, almost coffee straw like tube) and the other over to the vaccuum ball/cruise control.
Thread Starter
Instructor
Joined: Feb 2015
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From: Seabrook Texas
Fixed
Well, not wanting to leave a story unfinished, I finally fixed it. What happened was the actuator for the blower blend door was slightly broken and caused it to malfunction whilst it was going. Highly unlikely that it will happen again but it's fixed now :3