Engine Cooling System problems of the 2008 GMC Canyon

Vehicle sets an "ac off" fault message frequently. When this occurs, the temperature gauge goes to zero and the ac does not work. The truck is not overheating and no other faults are set. No trouble codes are found during scan. After some time (20-50 miles of travel), the fault disappears and the temperature gauge and ac begin working again. There are literally 1,000's of messages on discussion boards about this problem on numerous websites on different gm vehicles. People have changed one, some, or all components of their cooling system to no avail. The problem sometimes goes away for a few hours or a few months, but always seems to return. I had my vehicle to the gm dealership in may 2016 and the condition was unable to be duplicated at that time. I paid the dealership to do a complete servicing and inspection of the entire vehicle, which included the cooling system. No anomalies were found by the dealership. Since the problem continued, I replaced the coolant temperature sensor hoping it was a just a bad sensor/connector problem. This has not changed the condition in any way. My concern is that this is possibly an issue related to the actual placement of the temperature sensor. I'll explain with the following scenario: once the engine comes up to operating temp, the thermostat opens, and when the coolant begins to circulate, the temp sensor is left exposed, the temp gauge tanks, and the system kicks into a safe mode. While this is a great system safe response, I am prevented me from seeing a real overheat condition. I personally live and work in the mojave desert. In an environment where temperatures are commonly above 100 deg f, a properly operating vehicle cooling system can mean the difference between life and death. I can't be entirely sure if my coolant system really has a problem or is just giving false indications at this point.