2004 Chevy Blazer Not blowing Hot air.
 

My blazer is blowing only warm air (maby about 550? Temp here in minnesota was 1 degree today. Any ideas?

Do you know if it is actually switching the actuator door between hot and cold? If not does your 4x4 work? I say this because if it doesn't work you might have a vacuum issue. If you think all of that is fine then I would just give your heater core a good flush and see if that helps.

Mine was blowing luke warm air when I first got it. I flushed the heater core a few times real good and the heater started working good after that.

do you have enough water in the radiator?

That door is operated by an electric motor. But regardless, it's a good thing to check out.

The door that changes between cold and hot is actually vacuum operated, and I agree that you should try to flush out the heater core, quick easy and cheap to do, just don't use very high pressure water.

See "Air Temperature Door":

https://blazerforum.com/forum/attach...ine=1355331799

Sorry I was thinking about the mode door.

Yes mrspeedy69 the actuator door is working as is the 4X4. Diaita the radiator and reservoir are at proper levels. I went ahead and changed out the Thermostat with one at 195 degrees, this I think has solved the problem. The old one I beleave was stuck closed. I will more than likely go ahead and flush the heater core if I get some decent weather, couldn't hurt. Thanks to you all

Dont expect any "decent" weather here in MN until april now haha!

the bend door is the issue Check for vac over there if not the bend door might be damaged. They tend to break once they get old.

Thermostat is usually the culprit. if shes blowing hot now you scored.