The response from Wrenchtech is correct and I agree with it. The lack of refrigerant is the cause, the IHKA system will see the logic from the pressure switch and begin to work if there is enough refrigerant in the system, it won't require a reset. A/C systems require special tools and equipment to be serviced correctly. They also operate at high pressures and repairs should be done by trained technicians.
Sunday, January 30th, 2011 AT 4:44 PM