5. AIR CONDITIONING OPERATION THE A/C AMPLIFIER RECEIVES VARIOUS SIGNALS, I.E., THE ENGINE RPM FROM THE IGNITER, OUTLET TEMPERATURE SIGNAL FROM THE A/C THERMISTOR, COOLANT TEMPERATURE FROM THE ENGINE COOLANT TEMP. SENSOR (EFI WATER TEMP. SENSOR) AND THE LOCK SIGNAL FROM THE A/C COMPRESSOR, ETC. WHEN THE ENGINE IS STARTED AND THE A/C SW (HEATER CONTROL SW) IS ON, A SIGNAL IS INPUT TO THE A/C AMPLIFIER. AS A RESULT, THE GROUND CIRCUIT IN A/C AMPLIFIER IS CLOSED AND CURRENT FLOWS FROM HTR FUSE TO TERMINAL 1 OF A/C MAGNETIC CLUTCH RELAY → TERMINAL 2 → TERMINAL A–CAG OF ENGINE CONTROL MODULE (ENGINE ECU) → TERMINAL A/C → TERMINAL MGC OF A/C AMPLIFIER → TERMINAL GND → GROUND, TURNING THE RELAY, ON, SO THAT THE A/C MAGNETIC CLUTCH IS ON AND THE A/C AMPLIFIER OPERATES. AT THE SAME TIME, THE ENGINE CONTROL MODULE (ENGINE ECU) DETECTS THE MAGNETIC CLUTCH IS ON AND THE A/C AMPLIFIER IS OPERATING AND OPENS DIRECTION TO AVOID LOWERING THE ENGINE RPM DURING A/C OPERATING. WHEN ANY OF THE FOLLOWING SIGNALS ARE INPUT TO THE A/C AMPLIFIER, THE A/C AMPLIFIER OPERATES TO TURN OFF THE AIR CONDITIONING. • ENGINE RPM SIGNAL IS HIGH. • COOLANT TEMP. SIGNAL IS HIGH. • A SIGNAL THAT THE TEMPERATURE AT THE AIR OUTLET IS LOW. • A SIGNAL THAT THERE IS A LARGE DIFFERENCE BETWEEN ENGINE SPEED AND COMPRESSOR SPEED. • A SIGNAL THAT THE REFRIGERANT PRESSURE IS ABNORMALLY HIGH OR LOW.