Heater blowing cold air

Tiny
BNRANTHONY
  • MEMBER
  • 2005 CHEVROLET AVALANCHE
  • 11,600 MILES
How do I fix a heater blowing cold air when I turn on the heater? It only blows cold air.
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Thursday, December 1st, 2011 AT 7:01 AM

12 Replies

Tiny
KEN
  • ADMIN
Hello,

It sounds like you have temperature blend door actuator that is out and needs to be replaced. Here is a guide that has a video showing you how to fix the problem:

https://www.2carpros.com/articles/replace-blend-door-motor

Make sure hot coolant is getting to the heater core by checking the heater hoses in the engine compartment. Make sure the blend doors and temperature controls in the heater box are functioning properly.

Here are the diagrams to change the temperature air door motor (below).

Please let us know what you find.

Cheers, Ken
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Thursday, December 7th, 2017 AT 8:30 PM
Tiny
MARSHALL35@FUSE.NET
  • MEMBER
  • 2005 CHEVROLET AVALANCHE
  • V8
  • 4WD
  • 180,000 MILES
Heater blows cold air for about twenty minutes before it heats up.
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Thursday, December 7th, 2017 AT 8:31 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Check the air blend door and actuator, if okay could be coming from the HVAC control module itself.
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Thursday, December 7th, 2017 AT 8:31 PM (Merged)
Tiny
DAMSLIM
  • MEMBER
  • 2002 CHEVROLET AVALANCHE
  • V8
  • 2WD
  • AUTOMATIC
  • 20,000 MILES
Heater not working. I have flushed the radiator.
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Thursday, December 7th, 2017 AT 8:31 PM (Merged)
Tiny
GMTECH
  • EXPERT
Have you tried back flushing the heater core? You can try also running the vehicle and seeing if you have hot going into the heater core and seeing if you have hot coming out. If you do not the heater core is either plugged or faulty.
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Thursday, December 7th, 2017 AT 8:31 PM (Merged)
Tiny
SCOTTY DEE
  • MEMBER
Check the operation of the blend door on the passenger side below the glove-box. Verify the HVAC controller is sending commands to the blend door actuator. If the coolant level is correct, the thermostat opens and closes as it should, and the blend door works, the heater core could have debris. Does it have Dex-Cool that is older than three years in it?
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Thursday, December 7th, 2017 AT 8:31 PM (Merged)
Tiny
SHAKAZOOLOO8
  • MEMBER
  • 2007 CHEVROLET AVALANCHE
  • V8
  • RWD
  • AUTOMATIC
  • 140 MILES
When I turn on the heat I get cold air blowing out.
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Friday, December 8th, 2017 AT 5:04 PM (Merged)
Tiny
KEN
  • ADMIN
Hey Shakazooloo8,

This is a common problem, you have a blend door actuator that is out and needs replacement. Here is a guide that will help you:

https://www.2carpros.com/articles/replace-blend-door-motor

Please let us know happens so it will help others.

Best, Ken
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Friday, December 8th, 2017 AT 5:04 PM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 2004 CHEVROLET AVALANCHE
  • 65,000 MILES
My heat does not work on the driver side, while the heat works on my passenger side. All it does is blow out super cold air on the driver side. Once in a great while it will randomly work and blow out warm air but only lasts for minutes tops. The air conditioning works fine. Please help?
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Tuesday, July 31st, 2018 AT 9:03 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Door actuator on the drivers side may be bad as it controls the blend door. Common failure.

Roy
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Tuesday, July 31st, 2018 AT 9:04 PM (Merged)
Tiny
2CARPROS-ARCHIVES
  • MEMBER
  • 2004 CHEVROLET AVALANCHE
  • 62,000 MILES
I just put a new battery in my truck and now my air and heat will not work.
What can I do?
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Tuesday, July 31st, 2018 AT 9:04 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
First check for any fuses under the hood or inside that blew from the surge when reconnecting the new battery. If they are all okay, you got caught by one of GM's many tricks to get you to go back to the dealer. With newer vehicles you must never disconnect the battery. Use some type of memory saver to keep all the many computers' memory circuits alive. A heating control system failure is not one of the ways these vehicles normally act so I am hoping you find a blown fuse, but if not, the dealer will have to unlock or reprogram that computer.
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Tuesday, July 31st, 2018 AT 9:04 PM (Merged)

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