Chevrolet Malibu - AC issues

2011 malibu ac works on and off replaced thermostat with factory one replaced coolant temp sensor with factory . if ac dont work car stays on cold temp when ac works tenp gauge works . been to dealership not fixed yet

I presume you mean that at the times the AC seems to be working— produces reasonably cold air when you turn it “on” – then the dashboard engine coolant temperature gauge also reads as expected, mid-range. But at times the AC isn’t working — no cold air (& no explanation why as yet) — then the engine coolant temperature gauge doesn’t move above the setting when the key is “off”, engine coolant completely cold.

hmm … I guess the first question is pretty obvious: When the AC isn’t working, and the coolant temp gauge says the coolant is cold, is the coolant actually cold? Are the engine compartment fans turning on and off? Ask your shop to use a thermocouple to determine the temperature of the metal-part at the top of the radiator for example. And ask the shop to use their scan tool to see what it says the coolant temperature is.