I have a 06 Monte LTZ with an air con problem. My air con works when the outside air temp. is approx. 20 degrees celcius or colder. BUT when outside air is hotter then 20 degrees the air con light goes off and about every 15 seconds along with hearing the air con compressor going off and on. I have change the ambient temp sensor and still the same. I have check coolant and check the pressures in the system and it is accurate. Can anyone help please and thank you.