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No power to the heater blower motor

Tiny
JAMES WOLF
  • MEMBER
  • 2001 CHEVROLET SUBURBAN
  • 5.3L
  • V8
  • 4WD
  • AUTOMATIC
  • 274,000 MILES
I have replaced resistor relay, blower motor, and control switch module. Using a test light, I have power out of the resistor on all speed settings but still nothing on the blower motor.
Monday, October 19th, 2020 AT 4:32 PM

7 Replies

Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good evening,

I attached a wiring diagram for you to view.

https://www.2carpros.com/articles/how-to-check-wiring

Does the orange wire to the resistor have power with the key in the on position?

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

https://www.2carpros.com/articles/how-to-check-a-car-fuse

I attached a diagram of the connector for the resistor. Make sure the pin that I circled has power with the key on.

Roy

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Monday, October 19th, 2020 AT 4:53 PM
Tiny
JAMES WOLF
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  • 4 POSTS
Yes Roy, I have power on the G pin with the key in the on position and the fan setting to off.
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Monday, October 19th, 2020 AT 5:12 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, with the key on and the fan set to high, do you have power to the wire to Pin F?

That feeds the relay for the high blower relay in the resistor.

Roy
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Tuesday, October 20th, 2020 AT 1:19 AM
Tiny
JAMES WOLF
  • MEMBER
  • 4 POSTS
Hey Roy, after testing I do have power to pin F with the vehicle on and the fan set to high, as well as have confirmed power on other pins on their corresponding settings.
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Tuesday, October 20th, 2020 AT 10:13 AM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, thanks. If the blower is not working then the resistor is the issue as that controls the blower motor.

Roy
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Tuesday, October 20th, 2020 AT 11:31 AM
Tiny
JAMES WOLF
  • MEMBER
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The resistor was the first replaced component, and I have power coming out of the resistor on the red wire (normally purple, red on replacement) at varying voltages based on fan speed, after the resistor didn't fix the issue. I replaced the blower motor, and then the switch module. Still nothing from the blower fan though.
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Tuesday, October 20th, 2020 AT 12:17 PM
Tiny
ASEMASTER6371
  • MECHANIC
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Okay, with the fan commanded on, check for voltage on the black wire at the blower motor. Let us see if it has a ground.

Roy
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Tuesday, October 20th, 2020 AT 4:54 PM

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