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Heater question after search.

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

  1. JROSS

    JROSS 1/2 ton status

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    I have an 81' Blazer w/AC. Now that it has gotten cold I go to use my heater and the blower doesn't come on. After about 30 min of driving the blower then kicks on. The fan switch is new, but when the blower kicks on it squeaks for a bit and then runs fine.

    Could the Blower motor be stuck when its cold and then free up when it warms up? or could the switch be faulty on the slide lever to turn the heat on?

    Please help I need to figure this out before my windows decide to start fogging. /forums/images/graemlins/tongue.gif
     
  2. alec78

    alec78 1/2 ton status

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    If it is squeaking, it could be loosing a bearing in the motor. That might also be the culpret(sp) with it not coming on right away.
     
  3. Confedneck

    Confedneck 3/4 ton status

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    how much is a blower motor for your truck? buy one, plug it in and see if it comes on right away when you plug it in, or take yours and jump it straight off the battery to see if it comes right on..if it does, id look at the switch, its a stepped resistor style switch and may be bad..
     
  4. JROSS

    JROSS 1/2 ton status

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    When you say the switch, which are you reffering to. The switch that activates the blower when you switch from the off position to ac/heat pos., or the switch the controls the fan speed. The later of the two is new.
     
  5. Confedneck

    Confedneck 3/4 ton status

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    the fan speed switch, even being new its still possible to be bad, the other switch would not cause the blower motor to be inop...theres only 4 things it could be, the motor itself, the switch, the relay or the wiring..
     
  6. HarryH3

    HarryH3 1 ton status Author

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    Every GM vehicle of that era that I've ever owned developed the "squeak when cold" symptom. But the "no fan at all" problem can be caused by a bad blower control relay. It's under the hood, usually attached to the a/c box. Just follow the power feed wire back from the blower motor and you should find the relay. Sometimes you can remove the blower motor and put some light oil in the bushings and that will quiet it down. Worst case is that you'll need a new motor. They run about $25-30. A new blower relay is about $10.

    You can use a voltmeter or test light to see if there is 12 volts at the blower motor when it isn't running. If yes, then the motor is stuck. If no, the relay is probably bad. I've had several of them fail in the "no power to fan" mode, but occasionaly hitting a bump would knock it around enough to cause it to engage.
     

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