{"model":"mk4","model_name":"MK4 Supra","vehicle":"Toyota Supra A80 (1993–2002, 2JZ-GE / 2JZ-GTE)","document":"Electrical Wiring Diagram","section":"RFAC","section_name":"Radiator Fan and Automatic Air Conditioning","page":2,"pages_in_section":11,"title":"Air Conditioning Operation","section_header":"Air Conditioning","ocr_text":"5. AIR CONDITIONING OPERATION\nTHE 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.\n\nWHEN 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.\n\nAT 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.\n\nWHEN ANY OF THE FOLLOWING SIGNALS ARE INPUT TO THE A/C AMPLIFIER, THE A/C AMPLIFIER OPERATES TO TURN OFF THE AIR CONDITIONING.\n\n• ENGINE RPM SIGNAL IS HIGH.\n• COOLANT TEMP. SIGNAL IS HIGH.\n• A SIGNAL THAT THE TEMPERATURE AT THE AIR OUTLET IS LOW.\n• A SIGNAL THAT THERE IS A LARGE DIFFERENCE BETWEEN ENGINE SPEED AND COMPRESSOR SPEED.\n• A SIGNAL THAT THE REFRIGERANT PRESSURE IS ABNORMALLY HIGH OR LOW.","image":"https://tsrm.sasquatchvc.com/images/mk4-ewd/RFAC/RFAC_002.png","url":"https://tsrm.sasquatchvc.com/mk4/ewd/RFAC/2","prev":{"page":1,"url":"https://tsrm.sasquatchvc.com/mk4/ewd/RFAC/1","api":"https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/1"},"next":{"page":3,"url":"https://tsrm.sasquatchvc.com/mk4/ewd/RFAC/3","api":"https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/3"},"section_url":"https://tsrm.sasquatchvc.com/mk4/ewd/RFAC","section_api_pages":["https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/1","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/2","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/3","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/4","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/5","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/6","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/7","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/8","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/9","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/10","https://tsrm.sasquatchvc.com/api/pages/mk4/ewd/RFAC/11"],"note":"OCR transcript of a scanned Toyota factory manual page; verify critical values (torque specs, part numbers) against the image."}