Heater stopped blowing hot air

[c-cab23]

i have on 04 Yukon and the heat stopped blowing hot....it was working fine yesterday...I started the truck today to warm it up to melt all the windows as we got an ice storm yesterday and it's just blowing cold air...front and rear Heat are both blowing cold air...any suggestions ? Thanks

 

[MrBalll]

Check your actuators.
Does it blow hot if you put the heat temp as high as it can go?

 

[Z71Tahoe2004]

That does indeed sound like the blend door actuators (BDA).

First thing you can try is the putting the BDAs through a recalibration procedure. Sometimes they need to be reminded what they're supposed to do. Here's the link for that:

https://sparkys-answers.com/2011/08/hvac-actuator-recalibration-procedure.html

Once you've performed the recalibration procedure, check to see if you can get warm air. If not, you've probably got a bad actuator. The one that controls the air temp mix is above the passenger footwell. Here's a link to a video showing how to get that one pulled and replaced. The dude in the video is getting only warm air, but same problem/equipment location applies.

For reference, the BDA that controls the air flow direction (floor, front, and defrost) is above and slightly to the right of the driver's footwell. There are (4) BDAs on board, and that one's the hardest one to pull and replace. Sounds like your problem is temp, so you shouldn't have to worry about that one. Hopefully one or both of the links above will solve your problem.

Here's the Amazon page with the AC Delco replacement part. They're all the same size and fit regardless of location in the vehicle.

https://www.amazon.com/ACDelco-15-7...PH8763W8BDD&psc=1&refRID=ZCQVN9QNCPH8763W8BDD

Let us know how it goes.

 

[MrBalll]

Never knew those were so expensive. Really hope mine isn't bad. My heat only works when set to 90. Fortunately I'm in Texas so it's never really that cold here.

 

[Z71Tahoe2004]

I just updated the link. The original one I posted was linking to one that was WAY more expensive than they ought to be. They normally run $40-50 depending on where you buy. The link in my original reply reflects the new one.

 

[c-cab23]

Thanks for all your ideas of what could be going on....I will check that tomorrow.....one thing I did notice today is that there might be an issue with the heater core....one heater hose is hot and the other is cold....and the answer to your question MrBalll is it does not blow hot air at all..even with the temp setting all the way up

 

[c-cab23]

Well I figured it out...I recalibrated the blend door actuators but that didn't help....then I noticed that my coolant level in the overflow bottle looked a little low.....I added about 2 quarts of anti-freeze and that took care of the problem......I have real good heat both front and rear....simple fix....thanks for everyone's input

 

[MrBalll]

Good to hear. Glad you got is solved.

 

[Spoolin]

Now to figure out why your cooling system was low. Topped off, you may start smelling it after some drives and you may be on a new goose chase. Hopefully will be something small or nothing at all

 

[89Suburban]

Well I figured it out...I recalibrated the blend door actuators but that didn't help....then I noticed that my coolant level in the overflow bottle looked a little low.....I added about 2 quarts of anti-freeze and that took care of the problem......I have real good heat both front and rear....simple fix....thanks for everyone's input

Simple fix nice. I have a pin hole leak on one of the hard lines going from the firewall Tee to under the pass side floor board.