Its the bad factory thermostat (defective) , the voltage parameters are being violated thus triggering the inoperable temp gauge the computer thinks the engine is over heating so it turns off the a/c to prevent overheating thus triggering a a/c light indicator. I just had my thermostat and engine temp. Sensor changed. So far so good, no more a/c light off and engine temperature gauge inoperable.

 

Hey Boy, we have no idea what rig you are talking about.
Please put the model, year and engine in your posts.