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Blower works on one speed only

Tiny
CJOHNS238
  • MEMBER
  • 2001 CHEVROLET MONTE CARLO
  • 3.8L
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 305,000 MILES
I have put in 2 different resistors and blower motor. Still no other speeds. At the electrical pigtail that plugs into the resistor those terminals for each speed only have 6.5v. When blower motor is plugged in and you try different speeds the fresh/recirculating button A/C rear def buttons will either not light or half light and won’t turn off until you turn the key off to reset. If motor is not plugged in then no issues turning speed dial or other buttons on HVAC control module.
Any idea’s?
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Tuesday, November 26th, 2019 AT 11:32 AM

11 Replies

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

I attached a wiring diagram for you to view. You need to test for voltage to the blower resistor from the selector switch. If that is good, then you may have a bad blower relay.

Roy
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Tuesday, November 26th, 2019 AT 11:42 AM
Tiny
CJOHNS238
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So this is the second new resistor in a row with no change. The voltage at each speed terminal is around only 6v. Shouldn’t those terminals be at 12v? I have heard of the ignition switch being a poss issue, I have jiggled it with no volt change at the plug terminals. I do get 12v on high. So relay there is working.
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Tuesday, November 26th, 2019 AT 11:46 AM
Tiny
ASEMASTER6371
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The voltage should be 12 volts, not 6.

It does not mean the relay is good at all.

Looks like you need at least the selector switch. Make sure the brown wire going into the selector switch has battery voltage.

Roy
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Tuesday, November 26th, 2019 AT 11:55 AM
Tiny
CJOHNS238
  • MEMBER
  • 6 POSTS
Perfect. I will check out the voltage on the selector and replace it if there is 12v. Thank you for your help so far with this! I hate buying unneeded parts. :)
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Tuesday, November 26th, 2019 AT 12:06 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
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Tuesday, November 26th, 2019 AT 12:42 PM
Tiny
CJOHNS238
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  • 6 POSTS
Okay, so the voltage at the plug to the HVAC module is 7.25v. So I am guessing it is the ignition switch?
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Thursday, December 5th, 2019 AT 4:30 PM
Tiny
ASEMASTER6371
  • MECHANIC
  • 52,797 POSTS
Good possibility. Check the voltage at the fuse box as well.

Roy
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Thursday, December 5th, 2019 AT 5:09 PM
Tiny
CJOHNS238
  • MEMBER
  • 6 POSTS
Okay, I pulled out the ignition switch and all the wires had 12v except one. I think it was orange but it showed the same voltage as at the HVAC module. Do you know where I can find a wiring diagram for the ignition switch to the HVAC module etc? Thank you for the continued help! Oh and what fuse do I check?
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Thursday, December 5th, 2019 AT 5:47 PM
Tiny
ASEMASTER6371
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Sorry, sick the past day.

Yes, you need an ignition switch. I attached a diagram for you. That orange wire should have battery voltage on it.

With all the recalls for GM switches, call the dealer and give them your vin number and see if you are in that recall. You could get it done for nothing.

Roy
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Friday, December 6th, 2019 AT 12:56 AM
Tiny
CJOHNS238
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Just finished swapping out the ignition switch and bingo! That was the problem all along! Thank you for your guidance with figuring this out! Your greatly appreciated!
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Saturday, December 7th, 2019 AT 4:44 PM
Tiny
ASEMASTER6371
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You are welcome.

Always glad to help.

Roy
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Sunday, December 8th, 2019 AT 5:24 AM

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