Auto Air Conditioning & Heater Repair: heater fan speed, blower motor resistor, wire coils

Question
I replaced the heater fan & motor on my 1992 chevy pickup because on high speed the fan was so noisy.  Low, Medium and high all worked except for the noisy on high. Now the fan motor only works on high.  Any ideas?
Dewy  

Answer
Right next to the blower motor you will see a 3 or 4 wire electrical plug that plugs into a small unit held onto the firewall by 2 screws this is your BLOWER MOTOR RESISTOR. This controls all the speeds except HIGH.

Remove it and on the backside you will see 2 or 3 wire coils. If this is what you see, You have the correct component. REPLACE IT.

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