On the back of the a/c compressor is a temp shut off switch. This will interrupt power supply to clutch on compressor if temp exceeds some level.

If the refrigerant level gets ever so sligthly low the cooling effects of returning freon to compressor diminish and the switch will shut your comp off. Somtimes in hot weather when it is completely full of refrigerant it will still shut off. If it cools well when comp is on then I would suggest just bypassing the switch. You can see how it is wired if you look at side of compressor. The wire comes to comp and meets a connector and then it goes down to sw on back of comp and then back to another connector adjacent to first one. Unplug both connectors and plug the two together leaving the switch on back of comp out of circuit. The a/c system has a pressure switch or sensor depending on model that will cause compressor to be shut down if high side pressure is excessive.

FOOTNOTE: clean radiators and condensers (intercoolers also on models so equipped) need periodic cleaning with spray cleaner and a hose to dislodge debris from roadway and bugs that can restrict airflow. Spray Fantastik or some other similar cleaner on cool condenser/radiator and then wash through with garden hose. It is risky to do this with high pressure car wash wand as the spray may bend fins over and make airflow worse.

THIS CLEANING IS A GOOD IDEA ON A YEARLY BASIS.