Help me understand this system

[Snert]

I have a 2019 1500 5.7 E-torque big horn trim. Truck has dual climate control hvac system.

I would say over the past 3 weeks it occasionally acts up. When working normally A/C is good and cold. Occasionally when I start the truck, it blows warm air.
I give a good smack under the glove box and then it goes back to blowing cold air.
If I turn up the temp while system is in sync mode, it will warm up. You. An turn it up to 85 degrees and it will cook you in the cab.
Of you turn down the temp it will drop but seems to stay on the very warm to hot side.

I tried turning up the passenger side and the driver side down to see if it would isolate to one side or the other. Nope both sides stay warm.
If I then go to passenger side and give. Couple good flat hand smacks under the glove box, it will then go back to blowing cold air.

After about 5 or 6 times turning the truck off and back on it will go back k to warm.

I will assume this is a blend door actuator issue. Or could it be a temp sensor causing this? Are the actuators accessible by removing glove box and center stack?

Truck has 162,000 miles.

 

[theblet]

i was thinking blend door problem as well, just not sure how to fix them. You could always install an AC hack for now. At least it would be cold all the time.

 

[Snert]

Today's adventure. I start the truck this morning by the dash button. Starts and blows luke warm air with temp set at 64°. I go to passenger side and give it a couple thumps. Air blowing from vents starts to drop.

Go to 3 stores, each tike shutting truck of for about 30-60 minutes between shut down and start up.
On the start at 3rd stop, Luke warm air with hvac on auto and set to "LO" on the screen.
Decide to turn up temp on the passenger side to "HI", Driver side still on "LO" . Driver side still luke warm air, passenger side blowing out very hot air. Then decide to raise the drivers side and lower the passenger side.
The Temps swing and change, luke warm air now on passenger side and very hot on drivers side.
Go to the next store, trun truck off for about 20 minutes still blowing luke warm air. Decide to turn off the hvac all together and drive home with windows open. Get about 2 miles from home, hit the "Auto" button on the climate control. Both sides still in "LO" and starts blowing nice cold air out the vents. Get home and just shake my head.

Now, when I turn UP the temperature, once it goes above about 77° on the dash setting/display. You hear it change over, I will venture to say this is a blend door opening 100% for the heater core side.
When you turn the temp back down, you hear it change again. However the air flow slows down and the air is luke warm.
Outside temperature during all this today was mid to upper 80°.

If I start the truck and Cold air is coming out as it should. It will stay like that until at one random time I shut the truck off and restart it.