Ac hvac vacuum?
Thread Starter
Junior Member
Joined: Aug 2011
Posts: 58
Likes: 0
From: El Paso tx
Car: 1984 Firebird S/E
Engine: 2.8 carbed
Transmission: Warner T5 5 Speed
Ac hvac vacuum?
so i just got the little climate control running on my car. Blower motor works fine, just when it engages i only have defrost blowing under all settings, anyone have this problem or any suggestions? ive followed vacuum lines, and maybe have it open but not sure what would help. thanks everyone!!! 
Supreme Member
Joined: Dec 2012
Posts: 1,356
Likes: 15
From: northern VA
Car: 88 Sport Coupe Camaro
Engine: V6 2.8
Transmission: Borg-Warner T-5
Axle/Gears: RPO/GU6: 3.42
Re: Ac hvac vacuum?
When the car is running, is there a constant hissing sound that comes from behind the levers for the HVAC controls?
Member
Joined: Jan 2013
Posts: 129
Likes: 0
From: Knoxville, TN
Car: '89 Formula
Engine: L98 350
Transmission: 700R4
Re: Ac hvac vacuum?
If there is a constant hissing, this may be the answer. It worked for me.
https://www.thirdgen.org/forums/inte...anent-fix.html
https://www.thirdgen.org/forums/inte...anent-fix.html
Supreme Member
Joined: Dec 2012
Posts: 1,356
Likes: 15
From: northern VA
Car: 88 Sport Coupe Camaro
Engine: V6 2.8
Transmission: Borg-Warner T-5
Axle/Gears: RPO/GU6: 3.42
Re: Ac hvac vacuum?
If there is a constant hissing, this may be the answer. It worked for me.
https://www.thirdgen.org/forums/inte...anent-fix.html
https://www.thirdgen.org/forums/inte...anent-fix.html
Yep, that's the most likely fix for the only-blows-through-defrost-vents.
Driver will probably also notice better engine performance when that vacuum leak is eliminated.
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