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heater controls on a 78

Discussion in 'The Garage' started by muddhawg, Sep 22, 2003.

  1. muddhawg

    muddhawg Registered Member

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    I am lost on this one, bought my truck in July, the guy I bought it from said that fan only ran on low speed, so I thought okay, blower motors gone. Went out to test it last week with temps. starting to come down and found that motor is working in all 3 speeds, but when hooked up it runs constantly in low!! I checked the speed switch, but the power wire runs from hot side to switch to blower motor factory wiring, with no breaks in between except at resistor, and it seems fine. The temp selecter switchs are mechanical and have no electrical run to them, how do I turn fan off, with out having to pop the hood and unplug blower motor each time? I have never had this problem before. /forums/images/graemlins/confused.gif
     
  2. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    Blower fans in GM's always run on low when the key is on even when it's off. Works as intended.

    I suspect the reason is to keep the box from overheating because the heater core always is in the loop. The low and med settings are run through the resistor pack in the blower box under the hood. all is controled by that big relay on the side of the box. High is straight 12v and on a seperate feed from the distribution block on the fire wall to the left of the Brake booster.
     
  3. muddhawg

    muddhawg Registered Member

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    Cool, then I have nothing to worry about.
     
  4. R72K5

    R72K5 Banned

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    yep, its super-low /forums/images/graemlins/laugh.gif

    happy heating /forums/images/graemlins/laugh.gif
     
  5. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    if you want it off just pull the fuse in the fuse box thats what i do then during the winter months i put it back in /forums/images/graemlins/thumb.gif /forums/images/graemlins/thumb.gif
     
  6. muddhawg

    muddhawg Registered Member

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    oh crap, another mudhog /forums/images/graemlins/shocked.gif, and I thought I was the only one. /forums/images/graemlins/rotfl.gif
     
  7. mudhog

    mudhog THEGAME Staff Member Super Moderator

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    nope your not the only one /forums/images/graemlins/eek.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif /forums/images/graemlins/rotfl.gif
     

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