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A/C QUESTION

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by jimmyjack, Jul 25, 2003.

  1. jimmyjack

    jimmyjack 1/2 ton status

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    Location:
    Tucson Az
    I live in Tucson and it's reaaaaly hot here. I have A/C in my truck. It blows ice cold air. But it has no volume. The fan jumped out of my hand when I tested it. I tested the relay, it works like a champ. I was able to watch the blend doors operate, they work. And there are no obstructions in the intake vents. Am I missing something really obvious???????? I get in my friends pick up and the blower about knocks my hat off. /forums/images/graemlins/angryfire.gif Any ideas will be greatly appreciated.
     
  2. Jays Beast

    Jays Beast 1/2 ton status

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    Check the evap coil it may be dirty and need to cleaned, also check the fan rotation could be running backwards, or if not original fan may be the wrong size motor if was replaced at one time. Just a few ideas I could think of right now.
    Jay
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Location:
    Atlanta
    In addition to the blend door there is 3 vacuum operated doors. One vacuum pot is near the gas peddle on the side of the box, one is more or less behind the box and you can feel the hose for it by reaching over the the box in the same area as the blend door and one is the freash air flap...It's been a while but I think that pot is in the cowel at the base of the windshield. Any one of those lines off would cause a issue of where the air is going.

    The Vac feed goes through the fire wall near the box. Usualy a vacuum storage ball somewhere it connects to. Then a check valve in the line between the balll and the connection on the intake (using between the distributor and the carb where that connects).

    Check that stuff. shounds like the doors are not opening or the lines are crossed and opening in the wrong order. The blend door only routes air through the Heater core. It ALLWAYS goes the the A/C coils.
     
  4. shane74

    shane74 1/2 ton status

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    This may inadvertantly answer a question for me too. In my '74, the heater/ac controls do not work properly. They never have since I bought it. The air only blows out the bottom like the switch is set on the "heater" position. It does not matter what I do. I found the vaccum line (looks to be approx. 1/8" dia tube) coming out of the fire wall and hooked it to the vaccum ball which is mounted on the passenger side of the firewall. The only place I could find to mount it was on a plastic nipple that is behind the large tube that runs to a vaccum distribution block that is on the intake manifold. It still doesn't work. Any ideas?
     

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