Blower motor speed control

Tiny
EUGENE.GENTILE
  • MEMBER
  • 2001 CHEVROLET BLAZER
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 219,392 MILES
Hi, My 2001 Blazer blower motor only works on High. I had gone through the forum and replaced the resistor pack today, but the problem still exists. Hot and cold are ok, just the fan speed. I found two fuses inside the vehicle taht seem to apply and bot are ok.
Tuesday, March 23rd, 2010 AT 9:12 AM

10 Replies

Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Then it is most likely going to be the fan sped selector switch in the dash if you have replaced the resistor and it didnt fix it. If you have a meter, test for power into the resistor in different fan speeds, if there is no power into the resistor in anything but hi, the switch is probably bad
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Tuesday, March 23rd, 2010 AT 10:15 AM
Tiny
EUGENE.GENTILE
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  • 9 POSTS
Thanks Jack,

I do own a meter, but really do not know how to use it. Can you guide me?
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-1
Tuesday, March 23rd, 2010 AT 10:23 AM
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Ground the black lead of the meter (Good body contact), use the red lead to test for power at the tan wire on the resistor with the selector in MED position. If nothing there, the switch is bad
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Tuesday, March 23rd, 2010 AT 10:37 AM
Tiny
EUGENE.GENTILE
  • MEMBER
  • 9 POSTS
Hi Jack,

Thanks a million! As I began to remove the connector to the resistor pack, the blower came on. Apparently, I did not make good contact when I put the connector onto the new resistor pack.

All fixed! You guys and gals are great!
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Tuesday, March 23rd, 2010 AT 11:16 AM
Tiny
2CARPRO JACK
  • MECHANIC
  • 11,533 POSTS
Glad to hear you are getting air once again. Thanks for using 2Carpros. Com
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Tuesday, March 23rd, 2010 AT 12:54 PM
Tiny
MSB4013
  • MEMBER
  • 5 POSTS
  • 1999 CHEVROLET BLAZER
  • 6 CYL
  • 4WD
  • AUTOMATIC
  • 137,000 MILES
When the heat is turned on the control from 1-4 (low to high) only 3and for work, not 1 and 2 what could it be. Also the blower that flows the heat is make a grinding noise (almost sound like it is lose)
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Monday, December 28th, 2020 AT 11:06 AM (Merged)
Tiny
ALAVEL
  • MEMBER
  • 2 POSTS
The resistor is bad
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Monday, December 28th, 2020 AT 11:06 AM (Merged)
Tiny
MSB4013
  • MEMBER
  • 5 POSTS
Do you also know what the grinding noise is when heat is on
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Monday, December 28th, 2020 AT 11:06 AM (Merged)
Tiny
ALAVEL
  • MEMBER
  • 2 POSTS
Replace the fan motor bearings bad
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Monday, December 28th, 2020 AT 11:06 AM (Merged)
Tiny
DANAUTHIER
  • MECHANIC
  • 156 POSTS
The blower motor resistor would cause the loss of some of the settings, the noise would be caused by the bearings going out in the motor or debris in the impellor (Squirl cage)

A failing blower motor resistor and continuing to run the motor can damage the motor. If the motor is failing and making noise this will cause the motor to draw more power and damage the resistor.

If this is a recent problem, replace the reisistor. Pull and clean the debris from the motor. If there is no debris, replace the motor as well. If you are not sure about the motor, try spining it, if it spins free and quiet, it is ok. Other wise replace.

Hope this helps,

Dan
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Monday, December 28th, 2020 AT 11:06 AM (Merged)

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