Blower fan only works on high speed

RODHEIDE

MEMBER
2013 GMC SIERRA
6.0L
V8
4WD
AUTOMATIC
95,000 MILES

Blower fan will only work on high speed. Also A/C won’t work. Thought it might be related to blower problem. When A/C is turned on green light flashes a couple of times and then goes out.

Sunday, March 10th, 2019 AT 5:01 PM

11 Replies

SCGRANTURISMO

MECHANIC
4,897 POSTS

Hello,

This could be a problem with your Blower Motor Control Module. I have included a link to a guide down below.

https://www.2carpros.com/articles/low-or-no-air-flow-from-vents

I have also included instructions for troubleshooting your specific vehicle in the diagrams down below. Please go through both of these and get back to us with what you find out.

Thanks,
Alex
2CarPros

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Sunday, March 10th, 2019 AT 6:34 PM

CARLLEBLANC

MEMBER
1 POST
2006 GMC SIERRA
V8
2WD
AUTOMATIC
70,000 MILES

My 06 GMC trucks ac blower motor is acting funny. First the high speed stopping working, now the blower works every now and than like when it just won'ts to. I have been told that it could be the resistor. Could this be the problem and were and how can I check it out.
Carl

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

HMAC300

MECHANIC
48,601 POSTS

You need to disconnect the wire going to the blower and put a test light there to see if it is getting power on each part of the switch. If it does then it' s the blower, if not then you need to check your switch to see if that is sending the power to the resistor. If it does then it's probably the resistor. It is a rectangular block that isn't easy to change, as it right by the blower motor.

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

ROBSHAW

MEMBER
1 POST
2004 GMC SIERRA
5.3L
V8
4WD
AUTOMATIC
186,000 MILES

Fan control has stopped powering blower starting with speed 1& 2, after a year 3 stopped now4 has syopped I only have the highest setting, #5, that works. Switch problem or further

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

SATURNTECH9

MECHANIC
30,869 POSTS

Sounds like it might be a blower motor resistor card the way the certain speeds stopped. Sometimes the connector to the resistors also melt to the resistors and need to be replaced as well. Unless you have a multi meter and want to do some testing with me I cant tell you for sure its the resistor. But my first thought would be a bad resistor.

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

BOSSKOSIROG1

MEMBER
2 POSTS
2003 GMC SIERRA
90,000 MILES

Do not have anything on 1 thru 4 fan speeds only on 5/high speed. How do I fix this

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Replace the blower motor resister

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

BOSSKOSIROG1

MEMBER
2 POSTS

Where is the blower motor resister

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

It should be mounted on the HVAC box under the dash

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

BRUSHINVESTIGATIONS

MEMBER
1 POST
1996 GMC SIERRA
V8
2WD
AUTOMATIC
155,000 MILES

New blower motor installed. The AC gets cold but when changing speeds from low med high, etc. The fan speed increases slightly. However on high itseems like it is not blowing very hard.

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)

BLUELIGHTNIN6

MECHANIC
16,542 POSTS

If the blower motor is indeed working but you don't believe that it is pushing air out as much as it should for each speed it may be due a broken/loose vacuum hose. You will want to check behind the dash for a vacuum leak.

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Saturday, December 26th, 2020 AT 9:43 AM (Merged)