PTC Heater Circuit: Description

The PTC heater is installed in the heater unit and operates when the coolant temperature is low and normal heater operation is insufficient.

The A/C amplifier switches the circuit in the PTC relay and operates the PTC heater when the operating conditions (the coolant temperature is below 65°C (149°F), setting temperature is MAX. HOT, ambient temperature is below 10°C (50°F) and blower switch is not OFF) are met.

The PTC heater controls the number of the heater elements to be heated based on the electrical load and the amount of voltage generated. Therefore, when inspecting the PTC heater, be sure to turn off other electrical devices.