HVAC blower speed stuck on high

Tiny
SUESS.N
  • MEMBER
  • 2004 BUICK CENTURY
  • V6
  • 2WD
  • AUTOMATIC
  • 165,000 MILES
I recently got this car given to me. The blower for the HVAC would only go on Hi and the cigarette lighter wasn’t working. I checked the fuses and sure enough. I replaced the fuse for the lighter and the low blower and now they both work fine. I don’t see a fuse on the diagram for medium speed and that’s the only one not working and I’m not sure how to fix that part.
Sunday, February 13th, 2022 AT 2:18 PM

7 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,119 POSTS
Hi,

There isn't a fuse for medium speeds. If they are not working but the high and low are, either the switch itself is bad or the blower motor resistor is bad.

If I had to guess, I would replace the resister. If you are questioning if the resister is the problem, refer to the wiring schematic below. Locate the purple, light blue, and tan wires from the switch. With the switch in the related position indicated on the schematic, check for power at those wires. If you have power, replace the resistor. If there is no power, replace the switch.

Here is a link you may find helpful:

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

Let me know if you have other questions.

Take care,

Joe

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Sunday, February 13th, 2022 AT 9:12 PM
Tiny
SUESS.N
  • MEMBER
  • 4 POSTS
So, sorry this took so long to verify. But it wasn’t the resistor. It took me a long time to get it out, and I tested it before I put it all back together and it does the same thing with the new resistor. Is there a tutorial on switch replacement?
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Friday, April 1st, 2022 AT 7:48 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,119 POSTS
Hi,

I have directions for the removal and replacement of the HVAC control assembly. However, I need to confirm if the vehicle has automatic climate control or manual control.

Let me know.

Joe
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Friday, April 1st, 2022 AT 8:28 PM
Tiny
SUESS.N
  • MEMBER
  • 4 POSTS
It is manual climate control.
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Friday, April 1st, 2022 AT 9:40 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,119 POSTS
Hi,

I attached the directions below for the control assembly (manual control).

Take a look through these and let me know if they help.

Take care,

Joe

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Friday, April 1st, 2022 AT 10:51 PM
Tiny
SUESS.N
  • MEMBER
  • 4 POSTS
So just to clarify, if a switch is bad, I have to replace the whole climate control assembly?
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Sunday, April 3rd, 2022 AT 10:29 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,119 POSTS
Hi,

If the switch is bad, it is part of the control module. Have you checked the electrical connectors? You could have one that has failed (overheated/melted) causing this.

Let me know.

Joe
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Monday, April 4th, 2022 AT 1:42 PM

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