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Old 01-25-2018, 04:46 PM   #1
72 5500
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Heater fan only works on high

The heater fan on my 97 only works on high. Is the switch bad or maybe a fan relay?
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Old 01-25-2018, 05:54 PM   #2
Mr_Rich
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Re: Heater fan only works on high

This was copied from my schematic diagram book.
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1989 K1500 Chev. EC
Original owner; some of the aftermarket parts I've installed are Borla headers, Hypertech chip, Edelbrock water pump, and a Stillen rear disc brake conversion kit.
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1997 K2500 Chev. EC 7.4L/ 4L80E
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Old 01-25-2018, 07:08 PM   #3
b454rat
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Re: Heater fan only works on high

Resister. My 'hoe did the same thing, then nothing. Replaced it with good junkyard piece, now works on all settings.
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Old 01-25-2018, 10:14 PM   #4
hutcholdschool
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Re: Heater fan only works on high

I would guess it is most likely the blower motor control module resistor. I had one fail on me and had the same symptoms as you.
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Old 01-27-2018, 04:48 PM   #5
72 5500
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Re: Heater fan only works on high

Sounds easy enough, thanks
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