Vent stuck in defrost mode
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Junior Member
Joined: Mar 2011
Posts: 7
Likes: 1
From: Eastern NC
Car: 1988 Iroc
Engine: 89 Calloway Corvette 350
Transmission: 700R4
Axle/Gears: 3:73
Vent stuck in defrost mode
was driv8ng down the road the other day and it started raining. I switched to defrost anfterbit was over went back to max ac and it stays in defrost mode. Air is only coming out the top of the dash. Any ideas what or where to start. Also it has seemed to ave lost some velocity on the air coming out too. Any help would be awesome. Thank u.
Re: Vent stuck in defrost mode
The default mode is defrost, so when you get a vacuum leak in the HVAC system, you'll get defrost only. Check the vacuum lines under the hood, but you'll probably find that the valves on the actual HVAC control head are leaking. The clip that holds the valves together likes to fail.
https://www.thirdgen.org/forums/inte...anent-fix.html
https://www.thirdgen.org/forums/inte...anent-fix.html
Joined: Dec 1999
Posts: 5,964
Likes: 37
From: Hacienda Heights, CA
Car: 90 RS 'Vert, 88 IROC-Z, 88 Firebird
Engine: 305 ci tbi, 305 ci tpi, 350 ci tpi
Transmission: WC-T5, WC-T5, 700R4
Axle/Gears: 3.45, 3.27, 3.27
Re: Vent stuck in defrost mode
GM discontinued these years ago. I refurbish these and sell them on my web site. The part number is GM 16032395: A/C HEATER MODE SELECT VALVE, $28.50.
Lon Salgren
Top-Down Solutions
www.top-downsolutions.com
Lon Salgren
Top-Down Solutions
www.top-downsolutions.com
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