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73-87 Chevy _ GMC Trucks => Interior & Equipment => Heating, Ventilation & Air Conditioning (HVAC) => Topic started by: Sprinkler-Man on March 16, 2014, 10:08:54 am
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I can't seem to get any air out of my defroster vents I am not sure why...any help? My blower sometimes doesn't work when I switch the selector from heater to vent. Do I need a new selector panel or a new blower switch? My truck has factory air.
Thanks
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I assume it is an 80 truck that we are talking about since you did not say and that is what is in your screen sign in ?
Have you checked your cables that go from your dash mounted selector to the heater/AC box under the dash to verify they are working and moving ?
If so then you will need to move in to the inside of the box to see if the flap door is moving. Also I do believe, I might be wrong though, that your truck should have both mechanical and vacuum controls for the heater/AC.
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1980 GMC Sierra Classic. I have taken out the main ducts to the dash vents to get a better view. There does seem to be 4 vacume lines running to the vents but i cannot find the one that controls the defrosters. I will look more once it heats back up and I run the truck again.
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Go to the tech section and look up the service manual for your truck, it should contain a breakdown and appropriate diagrams.