If you know your way around a personal computer, then you might try VXDiag VCX NANO Diagnostic Tool for GM. It uses GM Global Diagnostic System 2 (GDS2) software with their version of a GM Multiple Diagnostic Interface (MDI) Tool to make the GM GDS2 software work.
Warning: it comes from Mainland China and will cause problems with virus protection (add exclusion for each file it finds), so use on a laptop dedicated as a scan tool only. Also, search YouTube for multiple videos on the VCX Nano GM.
Camaro with C68 Single Climate System, HVAC Control Module Example Data:
Note 1: Vehicles with C68 installed will show very high and low temperatures for right duct air temperature sensors.
Note 2: A failed duct air temperature sensor will show very high or low temperatures.
Another scan tool that could be used and not as powerful as the GM GDS2 is AutoEnginuity Giotto Version (acquired by Drew Technologies January 2020) with Enhanced GM-family Expansion.