Question about 2002 GMC Sierra

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Fan speed switch only works on #5

I have a strange problem with the climate control in my GMC 1500. The fan control does not work for speeds 1-4 but works fine on the highest setting of 5. The AC works fine and the air is cold on 5 plus I can feel cold air passively flowing when I have it on fan setting 1-4. There is also no fan motor noise on setting 1-4. Is this an indication of a malfunctioning switch (speed control)?


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  • Anonymous Sep 18, 2008

    Mine is a 2003.But it does the same exact thing.

  • Anonymous Mar 17, 2014

    Has climate control. Selector has auto ,1,2&3. No matter where it is set in any of those positions it may come on or may not. When it comes on will work at all speeds, when not it doesnt work at any speed setting.

  • Anonymous Mar 25, 2014

    no air flow at any speed



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Call your local GMC Dealer and see if they have the climate control panel in stock. What happens is the circuit board on the back of the panel shorts out. The panel comes as an assembly and is very easy to replace. Don't go with a wrecking yard piece. I made that mistake once and it didn't work either. I got one from the Chevy dealer and it worked perfectly.

Posted on Aug 21, 2008


It most likely the speed control resistors, it is a modual that is attached to the air intake duct to keep it coil. On any of the lower speeds the current passes through the resistors and reduces the voltage to the blower motor. On #5 or the highest speed the resistor modual is bypassed.

Posted on Aug 30, 2008


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