HVAC issue: no heat unless set at 90 degrees 07-14 Tahoe

[jared999]

pulling the hvac fuse or disconnection the battery for a couple minutes makes them self-calibrate, you can hear them doing it if you just turn the key on afterwards

I didn't see instructions for the 07-14 model year specifically, but tried to self calibrate several times based on 99-06 tahoe/sierra/suburban instructions and youtube video(s) that I found. I figured they would be the same.
Nothing worked.
1. set AC to auto.
2. disconnect battery for 2, 5, 10 and 60 minutes. (each one was a different attempt).
3. reconnect battery
4. turn ignition switch to on, but not starting the car. The AC defaults to 74 degrees.
5. wait for acuators to self calibrate.

Nothing happened.
I should mention - I replaced the mode actuator recently, which is why I need to recalibrate.

 

[Doubeleive]

I didn't see instructions for the 07-14 model year specifically, but tried to self calibrate several times based on 99-06 tahoe/sierra/suburban instructions and youtube video(s) that I found. I figured they would be the same.
Nothing worked.
1. set AC to auto.
2. disconnect battery for 2, 5, 10 and 60 minutes. (each one was a different attempt).
3. reconnect battery
4. turn ignition switch to on, but not starting the car. The AC defaults to 74 degrees.
5. wait for acuators to self calibrate.

Nothing happened.
I should mention - I replaced the mode actuator recently, which is why I need to recalibrate.

disconnecting the battery will make them self calibrate, doesn't matter what the control was set at. when you see the control go back to 74/74 then you know it has reset,
you can confirm by watching the center metal notch & marks in any of the actuators, you will see it move all the way forward and reverse and return to center.
you can also hear them moving they are rather quiet but if you listen carefully you can hear them, become one with the machine lol.

 

[jared999]

disconnecting the battery will make them self calibrate, doesn't matter what the control was set at.

Got it.

you can confirm by watching the center metal notch & marks in any of the actuators, you will see it move all the way forward and reverse and return to center.
you can also hear them moving they are rather quiet but if you listen carefully you can hear them, become one with the machine lol.

Well, I've never looked at any of the actuators when doing this. I suppose I can eyeball the one under / to the left of the glovebox. That's the easiest one to get to.
Based on results, though, the calibration hasn't worked for me. I'm only getting air from the front vents. not the top, not the bottom. The mode actuator was replaced with a new OEM GM actuator, btw.

Also, thank you for taking the time to respond to me in this thread I appreciate it.

 

[swathdiver]

They do self-calibrate with every ignition cycle, sort of. I've never been successful without using the Tech-2.

 

[jared999]

How long have you had the truck and was the headliner ever replaced? I've never seen without at least one but admittedly doubt I've seen them all!

I've had it for a few years. It's possible the headliner was redone, before I purchased it.

 

[jared999]

So at this point I will either locate a clone that can program things (not just spit codes) or find a shop with a tech 2. I'm in NW Houston so I'm sure it won't be hard to find a place.
My local chevy dealer is out of the question, unfortunately. They wanted an hour labor to program my new fob, which took me all of 2-3 minutes to do. That time spent includes walking to my tahoe and walking back into my house

I will report back once I have results. It may be a few weeks before I can buy one of those things.

 

[Doubeleive]

so you replaced the mode actuator? looked like this?

 

[jared999]

so you replaced the mode actuator? looked like this?
View attachment 368167

Yep, I replaced that with an OEM GM part when I pulled the dash out, even though nothing was wrong with the original as the modes worked fine. Mostly it was the thinking of "the dash is out replace everything".

 

[Doubeleive]

Yep, I replaced that with an OEM GM part when I pulled the dash out, even though nothing was wrong with the original as the modes worked fine. Mostly it was the thinking of "the dash is out replace everything".

if you still have old one you might try putting it back in and see what it does, if it works then that one may be no good. just speculation it shouldn't take a tech2 to make it work

 

[jared999]

if you still have old one you might try putting it back in and see what it does, if it works then that one may be no good. just speculation it shouldn't take a tech2 to make it work

I suppose new oem parts can be faulty, and I do have the old one. Based on what others have said here and else where, I'll try a tech 2 first before I pull the dash out again.