Air Conditioning/Blower not working

Tiny
JMACCOMBS5
  • MEMBER
  • 2004 CHEVROLET IMPALA
  • 117,000 MILES
My vehicle is a 2004 Chevy Impala. About five days ago my blower stopped working all of a sudden, so the fan would not blow any air at all (neither heat nor A/C). I hoped it could just be the HVAC fuse that had blown so I went and bought a 25A fuse to replace it. I replaced it and the blower started working again, although it was a little slower than it used to be. Yesterday the blower went out again though, so I now don't know if it was the fuse.

One thing I noticed in addition to the blower going out was that when I began to push on the gas pedal from idle/park, a screeching sound would start for about 5 seconds and stop once the car got going (a sound as if air or water was being released is how I would describe it).

Not sure if these two issues are related but they occurred pretty much around the same time. All my fluid levels are good (I just filled them up completely), as I thought it was maybe the power steering fluid that was low and making the noise (because this noise was in addition to me turning the wheel).

Thanks for the help!
Friday, July 27th, 2012 AT 2:51 PM

46 Replies

Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Have the blower fan motor checked. Looks like it is failing. Try giving thr blower motor housing some banging with your hands and if it starts working, the motor is due for replacement. Get this done and monitor if the noise goes away.
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Friday, July 27th, 2012 AT 2:57 PM
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
  • 2004 CHEVROLET IMPALA
2004 Chevy Impala 120000 miles

Blower motor on 2004 Impala stopped working, actually started smoking through vents. So I removed it and it was seized. I replaced the blower and it didnt work. Fuses are all working. Hooked voltmeter up to the blower wires and read zero volts, so I removed blower control module and checked voltage into it, which also read zero. The fuses for each show 12.7 V and 13.4 V respectively. Is there another part in between the fuses and module that im missing?
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Do you have auto climate control or manual a/c?Also what model impala do you have?Let me know and I will get you a wire diagram and trouble tree.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
It has manual a/c and the model is 3.4 L engine, Base model. Will definitely donate if I get it working.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
I emailed you a trouble tree and wire diagram to your personal email. Please post all your question's and finding's on this posted question so other user's can help fix there car.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
I found an Open Line between the Battery Positive Voltage Circuit C to the Ground A (I also tried gound on car both where OL) on the 5 Pin blower motor control processor.

I'm assuming that this means when the original blower motor started to go bad drawing to many Amps it burned out the wires and they need to be replaced or do I have to do something else.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
Terminal c at the blower motor control processor should have power going to it. Terminal a at the blower motor control processor should have a connection to ground. You Need to check those two seperate put the black lead to chassis ground then put the meter on dc volt's and test the Terminal c at the blower motor control processor should have power going to it. Now with the black lead still grounded put the meter on low scale ohm's take the red lead and see if you have less then two ohm's at Terminal a at the blower motor control processor. Let me know what you find for each reading.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
Terminal A does have a connection to ground and I can read 1700 Ohms between A and B, but A to C is an open line. I can read a small voltage of 0.1 V between A and B.

A to Chassis ground has 1.6 Ohms between them. C to chassis ground is Open Line.

Sorry it took me so long to get back I've been on vacation and its been too hot to do any work.

I've tried following the wires to under the hood but couldnt find where they come out.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
  • 30,869 POSTS
If you have 1.6 ohm's to ground on terminal a to the blower motor processor then that's good. For terminal c to the blower motor processor we are looking for power not ground. So ground the black lead of the meter and put the meter on dc volt's setting 12 volt's or above scale and take the red lead and test for power to terminal c if you don't have battery voltage there then see if you have power to the hvac blower fuse in the under hood junction block.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
I checked the blower motor fuse under the hood, (I had checked the fuses on the side of the car but not the ones under the hood) it was blown out of course.

So I went down and got a new 30 amp BUSS plugged it in and now the blower is running, but it is always running on high and never turning off even when the car is off. From the other posts I've read on here it seems like the blower control moduloe has gone bad too and needs to be replaced. Is that true?
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
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At least the motor runs too bad it won't shut off.I emailed you the trouble tree for blower motor always on. Try to work around the part where it asks you to use a scan tool. Let me know what you find.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
OMINOUSTS
  • MEMBER
  • 6 POSTS
I worked through the trouble tree and ended up replacing the blower control module. I installed it and everything works fine. Thanks for all the help!
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
SATURNTECH9
  • MECHANIC
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Glad to hear you got it all figured out. Thank you very much for your donation. Also thank you for using 2carpros.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
WMGREC
  • MEMBER
  • 1 POST
  • CHEVROLET IMPALA
I have a 2005 Chevy Impala. The blower motor was making noise & then stopped working altogether. I checked the fuses and they were fine. As the motor was making a noise before it quit on me, I replaced the motor and it still doesn't run. What else can I check and how can I check it?

Thanks
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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My suggestion is to check the blower motor resistor for power before you get to the control switch.
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Saturday, October 20th, 2018 AT 4:52 PM (Merged)
Tiny
PSJ011777
  • MEMBER
  • 34 POSTS
  • 2004 CHEVROLET IMPALA
Ok so the blower will not come on at all. I thought maybe it wasnt getting power so I took and ran a line straight from the battery to the blower control module, it still didnt come on. The lights behind the switch work, and the rear defroster works but not the main blower. I dont want to spend a fortune replacing the blower control module to find out its not that. What could the problem be?
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Sunday, October 21st, 2018 AT 6:28 PM (Merged)
Tiny
RASMATAZ
  • MECHANIC
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Why don't you power the blower motor direct from the battery and see what happens
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Sunday, October 21st, 2018 AT 6:28 PM (Merged)
Tiny
PSJ011777
  • MEMBER
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Good idea, I didnt even think about bypassing the module.
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Sunday, October 21st, 2018 AT 6:28 PM (Merged)
Tiny
PSJ011777
  • MEMBER
  • 34 POSTS
OK, so I hooked power to the purple wire going directly to the blower motor, only two wires, purple and black. Did not come on. Also, when I checked voltage to the plug that goes to the blower control module, there was no voltage to it either regardless of what position the switch was on.
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Sunday, October 21st, 2018 AT 6:28 PM (Merged)
Tiny
KHLOW2008
  • MECHANIC
  • 41,814 POSTS
Is this a manual or automatic AC control system?

Have you tried to check for trouble codes?
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Sunday, October 21st, 2018 AT 6:28 PM (Merged)

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