a/c comes out defroster ducts

1995 PONTIAC GRAND PRIX
19,000 MILES
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WEISSEGC
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  • 2 POSTS
a/c comes out defroster ducts and floor ducts when driving but out of a/c ducts while decelerating. Also, low air flow all the time in heat or a/c positions but blower is running at full speed

low air flow all the time / blower is running okay
Mar 20, 2012 at 8:44 PM
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HMAC300
  • ✓Experienced Mechanic
  • 48,601 POSTS
check your actuators in your heater unit, they direct air all over. sounds like you have a vacuum leak , pic included. try to find where it's leaking, could be leaking coming to the control head.
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Mar 21, 2012 at 8:34 AM
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WEISSEGC
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Thanks for the schematic and quick response. I figured the switching during decel was a vacuum leak, but the low air flow throughout all ranges (with strong blower motor) seems like something else. This car was not driven much (19,000 on a 1995) so could something be "plugging" air access? and where would I look?
Mar 21, 2012 at 8:29 PM
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DJCL
  • ✓Experienced Mechanic
  • 767 POSTS
Look for a cracked vacuum line where the lines go through the fire wall . Most likely to have a leaking vacuum line under the hood.
Mar 22, 2012 at 5:02 AM
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