temp gauge high and air blowing warm
First thing to do is check the coolant level in the radiator when it's cold. It should be filled to the top and the plastic recovery tank should be filled about half way. Since the air conditioning system puts an added load on the cooling system the computer disables the A/C if the engine overheats. That's normal. HTH. -Jim
I had the same issue. Did tons of research, took it to several shops with several different guesses and finally to GM. They told me it was the thermostat which I disagreed because it was mechanical and nothing from the thermostat is connected to the temp gauge. They explained it to me and it made perfect sense. If the thermostat is not working, the car will run too cold or too hot, too cold in my case. The computer is set for he car to run within a certain temperature range. If it does not, it will send a fault message, usually P0128 to the computer which will shut down the air conditions, set the temp gauge to C and make the fans run all the time. I had them change the thermostat and it fixed all the problems.
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