NO Heat and even colder air on deforst

Asked by Dec 20, 2013 at 02:52 PM about the 2002 GMC Sonoma SL 2WD

Question type: Maintenance & Repair

I have cool air coming out in heater mode.  I have already flush the radiator and also cleaned the heater cores.  What else can be causing this?

1 Answer

35,675

Stuck thermostat, air pocket, how did you test the heater core? Defrost blows cooler because the defrost uses the air conditioning to remove moisture from the air to defog the window quicker. Check the heater core lines for heat in both lines once the engine is up to temp. oif they are both pretty warm it could be the temp blend door isn't getting vacuum to it to open. If one line is hot and the other is cold then you have a blockage, if the engine is hot and both are cold then that's a serious blockage.

6 of 6 people found this helpful.

Your Answer

GMC Sonoma Experts

  • #1
    parkle
    Reputation
    710
  • #2
    Mike Bonnell
    Reputation
    480
  • #3
    James Mayfield
    Reputation
    320
View All

Related Models For Sale

Used Chevrolet S-10
13 Great Deals out of 1,205 listings starting at $1,600
Used Ford Ranger
201 Great Deals out of 5,575 listings starting at $995
Used GMC Sierra 1500
1,180 Great Deals out of 64,912 listings starting at $999
Used Chevrolet Silverado 1500
2,717 Great Deals out of 175,181 listings starting at $955
Used Toyota Tacoma
714 Great Deals out of 45,875 listings starting at $2,500
Used Ford F-150
3,267 Great Deals out of 223,477 listings starting at $1,200
Used Nissan Frontier
468 Great Deals out of 23,909 listings starting at $1,800
Used Dodge Dakota
84 Great Deals out of 3,638 listings starting at $1,499
Used Dodge Ram 1500
410 Great Deals out of 11,150 listings starting at $1,495
Used Toyota Tundra
701 Great Deals out of 34,411 listings starting at $1,500
Used Ford Explorer Sport Trac
55 Great Deals out of 1,817 listings starting at $2,395

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.