Heater on my 01 GMC Sierra doesnt fully work

Asked by Weezer67 Jan 22, 2013 at 06:22 AM about the 2001 GMC Sierra 1500

Question type: Maintenance & Repair

Last summer, on cool mornings, I noticed that the heater didnt start blowing hot air once up to temp. Later in the day when it was hot out, I went to turn the temp to cool, it kept blowing hot air for a long time until finally cooling down like the control wasnt working. Now when I need heat, its -7 below today, I find its blowing warm air when its up to temp. It gets alittle warmer when i am driving. Any possibility its the temp. control  rheostat on dash panel?

3 Answers
176,055

tenspeed answered 11 years ago

On other GM products, the temperature is controlled by a stepper motor that controls a bypass door. The door allows air flow around the core when open. --- It could be that the door is stuck open. It could be that not enough hot coolant is flowing through the core due to a clog or low flow from a worn water pump.

2 people found this helpful.
Mark helpful
69,055

John answered 11 years ago

Lots of them also have a large debris "filter" going to the heater core. Seen quite a few clogged with symptoms similar to yours. Back flushing the heater core will clear the blockage if that is the issue. I mentioned this in a previous post and found a site with a handful of people saying the same.  http://www.cargurus.com/ Cars/Discussion-t2226_ds531377 http://www.pacificp.com/forum/ viewtopic.php?t=977 both links there, delete the spaces.

3 people found this helpful.
Mark helpful

Your Answer:

Related Questions

Sierra 1500

Looking for a Used Sierra 1500 in your area?

CarGurus has 7,869 nationwide Sierra 1500 listings starting at $5,500.

Postal Code:

Shortcuts

Search GMC Sierra 1500 Questions

CarGurus Experts

  • #1
    yetilikesbeer
    Reputation
    12,350
  • #2
    dragonflyoffshore
    Reputation
    11,500
  • #3
    John Saffrahn
    Reputation
    11,440
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Chevrolet Silverado 1500
176 Great Deals out of 7,546 listings starting at $7,777
Used Ford F-150
311 Great Deals out of 13,471 listings starting at $4,888
Used GMC Sierra 2500HD
27 Great Deals out of 2,111 listings starting at $8,490
Used Toyota Tundra
35 Great Deals out of 938 listings starting at $10,698
Used Chevrolet Silverado 2500HD
28 Great Deals out of 1,611 listings starting at $8,999
Used Toyota Tacoma
41 Great Deals out of 752 listings starting at $9,975
Used GMC Yukon
17 Great Deals out of 934 listings starting at $5,890
Used Dodge RAM 1500
3 Great Deals out of 82 listings starting at $2,500
Used Ford F-250 Super Duty
34 Great Deals out of 777 listings starting at $2,890
Used Chevrolet Tahoe
20 Great Deals out of 774 listings starting at $7,499
Used Chevrolet Camaro
16 Great Deals out of 462 listings starting at $11,749

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.