What causes a thumping noise by the blower fan when I first turn the ignition on and later when I shut motor off? This noise lasts about 10 to 20 seconds.
that thumping noise is your air inlet door motor it needs to be changed they cost $40 to $65 depending on which one you have ,my truck does it and good luck getting that motor out it is a bear to remove i just put up with it , one day i'll get tired of the noise and fix it
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