Mechanics

96 AC/HEATER CONTROLS DO NOT WORK

1996 GMC Sonoma

I have a 96 gmc sonoma with 189k miles, and the swith contorl for the heater and ac goes on but it only blows out of the defrosters and floorboards. Both the heat and a/c work fine but the controls do not change where the vents blow out of. Thanks for the help.
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Gmcsonoma
June 20, 2007.




It sounds like you lost a vacuum hose under the dash somewhere. The vacuum controls the mechanism that controls the air flow selection.
You might be able to here the vacuum.
And if you; 're a smoker, blow smoke under the dash and follow it.
Or bad control valve

Tiny
Danimalgmc
Jun 25, 2007.
I'll try that, thanks for the help, I hope it works, its kind of annoying.
AD

Tiny
Gmcsonoma
Jun 25, 2007.

AD