2016 Premier HVAC issue

Some many months later numerous trips to dealer still no fix! Dealer says its normal I guess they think I'm a idiot!
In auto in HI OR AS LOW AS SETTING TO 86 WORKS FINE!

If I drop tempature lower to 81 degrees say in Auto Mode it blows cold driverside warm air on passengerside . If I switch out of Auto Mode to VENTS it will flow warm air on driverside!

Basically it will not vary temperature below 86 degrees just goes cold driverside as well as rear seating!!
Can anyone help explain or tell me where the cabin tempature sensor for the driverside is?

Greatly appreciated.

There's no codes dealer supposedly has replaced actuators etc etc they're no help. Has been in shop atleast a dozen times under warranty mind you no fix. To say I'm aggravated is beyond imagination

Dealer says they've done everything they can will not admit defeat says that's the way it works, I say BS! I offered to rent bring another 2016 malibu there and if it works like mine I'll eat crow!! They said nothing anyone want to meet me with a 2016 in WTBY CT at Blasius??