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  1. #1
    Jr. Apprentice
    Join Date
    Feb 2008
    Location
    South Florida
    Posts
    26

    Default Heater control valve question

    Well just had my A.C. recharged for the summer. A.C shop told me that my heater control valve is bad due to hot hoses going past the valve to the heater core. Well I just replaced the control valve and same thing happens. If I pull off the hose at the valve there is no vacuum on the hose with the AC on. If I turn the heater on still no vacuum at the hose. I suspect that valve on the other end of the hose is bad. Does anyone know what it is called? Can it be bought at a parts store?

    Currently I have staight manifold vacuum going to the valve and the hoses are now cool. I suspect that heat off=vacuum
    heat on= no vacuum.

    Opps almost forgot this is a 1999 K1500 dual A.C

  2. #2
    Jr. Apprentice
    Join Date
    Feb 2008
    Location
    South Florida
    Posts
    26

    Default

    Just keeping this thread alive, Anybody know this valves name?

  3. #3

    Default

    I'll do a little looking and see what I can find out.
    Gary

    99 K 1500 Suburban
    78 Silverado Big 10 w/factory 454
    00 S-10 Blazer
    1976 Trans Am
    1980 Honda CB900 Custom

  4. #4

    Default

    I couldn't find anything, but I went and checked my Suburban. I did not have any vacuum on that line either and my hoses were hot. My A/C works fine, so I'll probably just leave it alone. I kind of like the fact that water is constantly flowing thru the heater core, it gives it less of a chance of gunk building up in there.
    Gary

    99 K 1500 Suburban
    78 Silverado Big 10 w/factory 454
    00 S-10 Blazer
    1976 Trans Am
    1980 Honda CB900 Custom

  5. #5
    Jr. Apprentice
    Join Date
    Feb 2008
    Location
    South Florida
    Posts
    26

    Default

    I see your point if it's not broke don't fix it. I unfortunately like to fiddle with things. It just bothers me that that the heater core is hot when I don't need it to be. I would imagine that some of that heat migrates past the shutter door into the evaporator section. Down here in Florida every little bit helps with the A.C.

    On another note. Do you think that valve is a Open / closed function or variable?
    1999 K1500
    Magnaflow muffler
    3 angle valve job
    Everything else stock
    Nice and clean!

  6. #6

    Default

    It is either opened or closed. It uses the blend door in the cabin to control the temp. Let me know what you come up with for a solution.
    Gary

    99 K 1500 Suburban
    78 Silverado Big 10 w/factory 454
    00 S-10 Blazer
    1976 Trans Am
    1980 Honda CB900 Custom

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