Topic: everything blows out the defroster
in Forum: C4 Cooling and Heating Systems
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Joined: 3/20/2009
Posts: 611
Vette(s): Black 1979 L-82
Black 1996 LT1
Black 1999 Coupe
Tony B said:
no matter what mode I select on the A/C / heat control on my 1990 everything blows out the defroster. Is there a diverter that needs to be replaced?
Check for vacuum lines for leaks, and the mech. that opens and closes the damper-doors that re-directs air from vent to defroster....it's free, and easy to check.
Similar to this (but on your car):
Remove the pass side fuel rail cover. There is a vacuum valve that may have deteriorated?
My 96 did the same thing, I had to remove the air control module which is located under the dash above the gas pedal. I removed the box and found that the lines ran through a black rubber which had nipples which collapse after time. I purchased new lines and removed that black rubber piece totally and joined the new lines to the control module. After doing this my air blows out the vents on the dash when needed and the floor for heat. I was informed on another forum that the default setting is defroster. Mine works like a champ. Good luck it was a b>>>>h standing on my head and removing the unit from under the dash.
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Joined: 7/29/2011
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Vette(s): 1973 Mille Miglia Red LS5
1981 Claret Red
1982 White
1985 Silver Metallic
1988 Yellow
1993 Torch Red ZR-1
1994 Torch Red Coupe LT1
1996 Dark Purple Metallic LT4
2000 Torch Red
2001 Light Pewter
2003 Z06 Millennium Yellow
2009 Atomic Orange
tloftus3 said:
My 96 did the same thing, I had to remove the air control module which is located under the dash above the gas pedal. I removed the box and found that the lines ran through a black rubber which had nipples which collapse after time. I purchased new lines and removed that black rubber piece totally and joined the new lines to the control module. After doing this my air blows out the vents on the dash when needed and the floor for heat. I was informed on another forum that the default setting is defroster. Mine works like a champ. Good luck it was a b>>>>h standing on my head and removing the unit from under the dash.
Correct on everything...defroster default is pretty much standard on most vehicles if there's an issue with the A/C system.
Also, spend 15-20 minutes to remove the drivers seat first, makes it much easier to recline and work under that dash.
1981 Dark Claret Metallic - SOLD
1982 White
94 Torch Red LT1
96 Dark Purple Metallic LT4
02 Black Convertible - SOLD
03 Millennium Yellow Z06
09 Atomic Orange Z51
09 Atomic Orange Z51
in Forum: C4 Cooling and Heating Systems
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