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Heater controls <<update>>

Discussion in '1982-Present GM Diesel' started by blasterD, Feb 20, 2004.

  1. blasterD

    blasterD 1/2 ton status

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    I just bought an 86 K30 with a 6.2 and a 465/205. The truck only has 64,000 miles and It runs great except for one thing. The heater controls don't work. The fan works, and the heater core is good, but it won't switch between defrost, vent, heater, etc. My '78 (gas engine) did the same thing and it was because the vaccuum line had a leak. Do the heater controls on a diesel operate off vaccuum as well? I'm new to the diesel scene and haven't had much experience working on them. Any info would be greatly appreciated. /forums/images/graemlins/thumb.gif
     
  2. u2slow

    u2slow 1/2 ton status

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    Re: Heater controls

    The AC heater controls do use vacuum - even on the diesel. The diesel has a vacuum pump in the "distributor hole" for this purpose.
     
  3. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    Re: Heater controls

    [ QUOTE ]
    I just bought an 86 K30 with a 6.2 and a 465/205.

    [/ QUOTE ]

    /forums/images/graemlins/waytogo.gif /forums/images/graemlins/waytogo.gif

    That's a beautiful drivetrain combo... /forums/images/graemlins/peace.gif

    Rene
     
  4. blasterD

    blasterD 1/2 ton status

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    Re: Heater controls

    Thanks for the info, I'm going to check it out today. /forums/images/graemlins/thumb.gif
     
  5. blasterD

    blasterD 1/2 ton status

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    I replaced the vacuum pump today. I found one for $130 at my local CarQuest. It now pulls more than 20" of vacuum. The heater controls work, but I still think there is something wrong. The fan sounds like it is working right but there doesn't seem to be much air coming out. It looks like the fan has been replaced before, but it doesn't look new. Is it possible that the PO put the wrong fan in? Does anybody have any ideas?
     
  6. HD

    HD 1/2 ton status

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    I had a prblem with the fan on my '75, I heard the motor, but not much air was being blown. I took the fan up and I found that the fan wheel would only turn about once for every five rotations of the motor. Where the fan wheel connects to the motor was worn baddly. So I got a new fan wheel and that took care of everything. Good Luck! /forums/images/graemlins/thumb.gif
     
  7. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    I was pretty unimpressed with my heater fan after I swapped to non-AC stuff. The non AC uses a weaker motor and a smaller squirrel cage so it moves considerably less air. I found an air leak between the heater box and the firewall so I sealed that.

    I then removed the stock fan motor and swapped an AC blower motor in it's place. I had to swap the smaller squirrel cage onto the AC motor and grind the flats a little farther on the shaft, but it does work...and it does push considerably more air.

    Alternatively you should be able to get a factory HD heater motor...it'll have a rubber hose attached for extra cooling of the motor.

    Rene
     
  8. blasterD

    blasterD 1/2 ton status

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    I believe I have the factory HD blower. There is a rubber hose connected to the motor. The truck has A/C too, although it doesn't work. I'm going to see if I can find any leaks. Thanks for all the good info guys. /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  9. tRustyK5

    tRustyK5 Big meanie Staff Member Super Moderator GMOTM Winner Author

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    The AC motor is the bestest one you can get. /forums/images/graemlins/smile.gif

    Hopefully Canmore pipes up...he had heat problems and it was a broekn plastic part on the blend door. The blend door wouldn't close all the way in either postion.

    Rene
     

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