A/C only blowing from defrost vents on dash pad
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Junior Member
Joined: Aug 2006
Posts: 12
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From: Aviano AB, Italy
Car: 1986 Pontiac Firebird
Engine: Custom built 350
Transmission: 700R4
A/C only blowing from defrost vents on dash pad
I'm just trying to figure out why when I turn on my A/C that the air only comes out of vents in the top of my dash pad. It doesn't come out of any of the other adjustible vents in the dash itself or from the lower vents in the radio pod. Can someone please help? Thanks. By the way, I just have a regular '86 Firebird.
Junior Member
Joined: Mar 2007
Posts: 59
Likes: 0
From: Staten Island, NY
Car: 1984 Camaro Z28
Engine: 350 from an elcamino
Transmission: stock t-5
Axle/Gears: 10 bolt 3.73 limited slip
Re: A/C only blowing from defrost vents on dash pad
I beleive the systems are run by vacuum, as in other cars. Check the main vacuum line, and the vacuum control switch in the dash.
Supreme Member
Joined: Feb 2004
Posts: 1,581
Likes: 3
From: So Cal
Car: 89 IROC Z28
Engine: 357 TPI
Transmission: 700R4
Axle/Gears: 3.42 Posi
Re: A/C only blowing from defrost vents on dash pad
It is the AC and heater control itself. If you unbolt it you'll see the vacuum lines on the back of the controls.
Joined: Aug 1999
Posts: 19,282
Likes: 103
From: Lawrence, KS
Car: Met. Silver 85 IROC/Sold
Engine: 350 HO Deluxe (350ci/330hp)
Transmission: T-5 (Non-WC)
Axle/Gears: Limited Slip 3.23's
Re: A/C only blowing from defrost vents on dash pad
Defrost is the default when a vac problem occurs. The piece is in the following pic is often the culprit:
https://www.thirdgen.org/forums/atta...duct010707.jpg
More info:
https://www.thirdgen.org/forums/inte...ht=control+vac
JamesC
https://www.thirdgen.org/forums/atta...duct010707.jpg
More info:
https://www.thirdgen.org/forums/inte...ht=control+vac
JamesC
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Joined: Sep 2007
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Re: A/C only blowing from defrost vents on dash pad
https://www.thirdgen.org/forums/at...duct010707.jpg
What color is the wire that goes from the control to the engine?
I read that there should be a hard black plastic vacuum line but I don't see it or a spot for it on the control assy.
What color is the wire that goes from the control to the engine?
I read that there should be a hard black plastic vacuum line but I don't see it or a spot for it on the control assy.
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Junior Member
Joined: Mar 2007
Posts: 59
Likes: 0
From: Staten Island, NY
Car: 1984 Camaro Z28
Engine: 350 from an elcamino
Transmission: stock t-5
Axle/Gears: 10 bolt 3.73 limited slip
Re: A/C only blowing from defrost vents on dash pad
the control line is attached to a vacuum canister by the braake booster on my car. the line is black up to the fire wall, and violet inside.
Joined: Aug 2009
Posts: 1,821
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From: Central California
Car: 92 Camaro RS
Engine: LO3
Transmission: T5
Axle/Gears: stock
Junior Member
Joined: Nov 2019
Posts: 16
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Car: 88 Camaro Iroc Z
Engine: 5.7 tpi
Transmission: Auto
Re: A/C only blowing from defrost vents on dash pad
I’m not sure how my reply ended up in here yesterday, I was replying to someone selling dash parts. My email address is averywelter@gmail.com , thanks
Joined: Aug 2009
Posts: 1,821
Likes: 40
From: Central California
Car: 92 Camaro RS
Engine: LO3
Transmission: T5
Axle/Gears: stock
Re: A/C only blowing from defrost vents on dash pad
I’m not sure how my reply ended up in here yesterday, I was replying to someone selling dash parts. My email address is averywelter@gmail.com , thanks
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