these are usually signs of the vehice engine cooling system reaching an overheating or is in overheating stage - I think those veicles are equipped with some kind of sensor to turn off or disengage the ac clutch when the car senses a raise in water temp in the engine that is too high above normal.I would suggest you check in to make sure the engine water coolant temp is running in top shape before the next step is made which will be to check into the AC system itself.