1993 GMC Suburban No heat

Discussion in 'Chevy Truck Forum' started by lclhawnboy, Jan 17, 2012.

  1. lclhawnboy

    lclhawnboy Member

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    I have a 1993 GMC suburban and the heater doesn't work. I hear the blower motor turn when I turn the key to ignition. I also don't see any lights on the air controls also air controls don't work. Any suggestions?
     
  2. chevychase

    chevychase Semi-Admin
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    Check fuses to start.. Maybe head unit /control panel. Check for power at unit.
    Will try to find a wire diagrahm.
     
  3. chevychase

    chevychase Semi-Admin
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  4. UncleBigBad1968

    UncleBigBad1968 Senior Member

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    If your thermostat is working, you can feel your heater hoses going into the firewall, both should be realitivley warm. You wont be able to hold on to them for a few min, cuz it will/should be slightly too warm to hold. If one is hot, and the other is cold then your heater core is clogged. Try to flush it first.
     
  5. dirtrider73068

    dirtrider73068 Moderator
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    If the heater core is clogged best to just change it, if you try to flush it may bust the heater core thus making it leak. Can you change form vent to defrost to floor if so your controls are fine, then the issue comes to the mode door, there are 3 the heat/cold door could be messed up, chevy's are known for this from what i have read, Ihave this issue, a gear inside cracks and gets stuck or won't work, your temp adjustment arrows should flash if this happens. If thats the case its about 100 buck for that mode door motor, but if you can get it out, take it apart the main gear that is/if cracked can be removed turn 180 degrees and put back together to work to get by, this I know did it to mine.
     
  6. lclhawnboy

    lclhawnboy Member

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    Thanks I checked the heater fuse and it was fine. So next step change the thermostat.
     
  7. lclhawnboy

    lclhawnboy Member

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    Thanks I checked the heater fuse and it was fine. Next step change out the thermostat.
     
  8. formulabruce

    formulabruce Senior Member

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    AT least take off the heater hoses and blow through them, please???
     
  9. dirtrider73068

    dirtrider73068 Moderator
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    You don't have to blow through the heater hoses, all you need to do is feel of the hoses hen the truck is warm will tell you just as better.
     
  10. UncleBigBad1968

    UncleBigBad1968 Senior Member

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    If the heater core is clogged best to just change it, if you try to flush it may bust the heater core thus making it leak.

    Never had a leak after I flushed mine. But in case it does then replace it. Might as well save a few bucks, and a headache. It is not easy pulling that dash apart to change the core.
     

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