2005 Buick La Crosse Heater blowing cold air

Tiny
BRUCE_COVEY
  • MEMBER
  • 2005 BUICK LA CROSSE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 48,000 MILES
Have just noticed the problem, since it hasn't been that cold in Georgia. Have done some extensive research on AllData. There is no control valve for the heater core that I can find. The upper supply hose is quite hot, but the lower one is fairly cool. IF I turn the HVAC system off completely, the lower hose heats right up. As soon as I turn the system on, it tries to blow hot air for a few seconds, goes basically lukewarm, and then I notice that the lower hose goes cool. I have pulled the HVAC/ECACs fuse and done the reset procedure. As near as I can tell, the control actuators seem to be moving as I change temp settings. It is almost as if the heater core has become clogged. Could this possibly be?

Thanks
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Sunday, January 18th, 2009 AT 3:06 PM

5 Replies

Tiny
RASMATAZ
  • MEMBER
Both of the heater hoses should be equally hot if the heater core is not clogged-up-did you check the thermostat?
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Sunday, January 18th, 2009 AT 3:19 PM
Tiny
DEPUTYCOLTON
  • MEMBER
  • 2005 BUICK LA CROSSE
Heater problem 6 cyl Front Wheel Drive Automatic

My cars heat run me out last year. No heat now. We changed the thermostat and still no heat. The car is running fine. The blower is working normally. Could it just need the system flushed?
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Wednesday, December 27th, 2017 AT 4:02 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

This sounds like you have a temperature blend door actuator that is not working. Here are two guides that will give you an idea on how to change it.

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

and

https://www.2carpros.com/articles/car-heater-not-working

Here is the location for your car (below) You are going to want to replace the mode actuator I have found the dual climate actuator as well which is the right on signal controls.

Check out the diagrams (Below)

Please let us know what you find. We are interested to see what it is.

Cheers, Ken
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Wednesday, December 27th, 2017 AT 4:02 PM (Merged)
Tiny
DEBO312
  • MEMBER
  • 2006 BUICK LA CROSSE
  • 3.4L
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 79,000 MILES
Car heater only blows cold air even if car has been stting or driven on the highway. Checked heater core hoses top one is hot, but the bottom one is cold. Car does not overheat and the coolant is at the max level. The fans are blowing and there is no leakage inside of car.
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Wednesday, December 27th, 2017 AT 4:02 PM (Merged)
Tiny
SATURNTECH9
  • EXPERT
Sounds like you have no flow thru the heater core.
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Wednesday, December 27th, 2017 AT 4:02 PM (Merged)

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