Diagnostic Flowcharts

Flowchart-Heater Core Temperature Sensor (Part 1 Of 2):

Flowchart-Heater Core Temperature Sensor (Part 2 Of 2):

Self-diagnosis indicator light D comes on: Indicates a problem in the heater core temperature sensor circuit. Use a digital multimeter (KS-AHM-32-003) to check it.

The heater core temperature sensor is a temperature dependent resistor (thermistor). The resistance of the thermistor decreases as the engine coolant temperature increases.