PTC HEATER CONSTRUCTION [FULL-AUTO AIR CONDITIONER]


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Outline

•  The PTC heater is supplementary heater to assist A/C unit heating performance.
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System Wiring Diagram

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System Block Diagram

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Operation

•  The climate control unit outputs a PTC heater operation request signal to the instrument cluster according to the ambient temperature signal, engine coolant temperature signal, and temperature control dial position information sent from instrument cluster by serial communication. The instrument cluster controls the PTC heater by operating PTC heater relay No.1/No.2 according to the ambient temperature and engine coolant temperature signals.
•  PTC heater operation is stopped if the following conditions are met:
―  The ignition switch is in the LOCK position, or the engine is not started
―  The engine is cranking
―  The engine is stalled
•  The PCM temporarily stops PTC heater operation to prevent lowering of engine startability caused by high electrical current use during PTC heater operation.
•  If the current/voltage information signal (present current, inputable current, and battery voltage) which is input from the PCM is lower than the specified value, the instrument cluster restricts the PTC heater operation pattern.