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HVAC Blower Motor Only Runs On Highest Setting


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cycleman54
Novice

Dec 4, 2011, 10:01 AM

Post #1 of 6 (1776 views)
HVAC Blower Motor Only Runs On Highest Setting Sign In

I am working on a 2001 Pontiac Grand Prix, 3.1 V6, with over 100,00 miles. The HVAC is manually controlled, 5-speed blower, with driver and passenger temp. control. The blower motor only comes on at the #5(highest)
setting. The blower motor also makes a whining, whirring noise when running. I checked the wires at the connector on the back of the switch with a multimeter. With key on, HVAC switch off, there is 11.7v at the orange(hot) lead, -.27v at the other wires except the brown wire(which I believe is the speed 5 wire) which shows 0v. With the key on, the position 1,2,3,4 wires show 11.7v and orange shows -.13, and the fan doesn't run. On position 5, the orange and brown wires show 10.95v and the fan runs. Does this sound like a faulty switch? The blower motor relay is incorporated in the blower motor resistor assembly on the HVAC control module.


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 4, 2011, 10:14 AM

Post #2 of 6 (1769 views)
Re: HVAC Blower Motor Only Runs On Highest Setting Sign In

You likely have a burned out blower speed resister causing the loss of blower speeds but this was probably caused by excessive current draw from a blower motor that is failing. I would replace both.



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We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



cycleman54
Novice

Dec 4, 2011, 10:40 AM

Post #3 of 6 (1752 views)
Re: HVAC Blower Motor Only Runs On Highest Setting Sign In

Thank-you for the quick reply. I suspected that I was dealing with something other than a switch problem and I sought the input of someone who had more experience in electrical trouble shooting. Your help is
appreciated. Cycleman54


Hammer Time
Ultimate Carjunky / Moderator
Hammer Time profile image

Dec 4, 2011, 10:50 AM

Post #4 of 6 (1743 views)
Re: HVAC Blower Motor Only Runs On Highest Setting Sign In

The switch is always a possibility but the resister is far more common.



~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

We offer help in answering questions, clarifying things or giving advice but we are not a substitute for an on-site inspection by a professional.



liltruckjr
Novice

Jan 21, 2012, 3:24 PM

Post #5 of 6 (1689 views)
Re: HVAC Blower Motor Only Runs On Highest Setting Sign In

Agreed, replaced module on 05 grand prix and only lasted about 2 months then replaced again and blower moter... no problem for a yr soo far..


Tom Greenleaf
Ultimate Carjunky / Moderator
Tom Greenleaf profile image

Jan 22, 2012, 6:48 AM

Post #6 of 6 (1683 views)
Re: HVAC Blower Motor Only Runs On Highest Setting Sign In

liltruckerjr - this thread is from Dec 4, 2011 on a 2001 not a 2005 model year and original person probably is all set and done with what Hammer Time suggested. Please read dates as this one is done,

T







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