Chart 1C-4 Insufficient or No Heating

CIRCUIT DESCRIPTION
Based on the various temperature sensor inputs, sun load sensor input, input from the PCM and the set temperature, the H-A/C control determines the required temperature and delivery mode to achieve and maintain the selected comfort level.

DIAGNOSTIC AIDS
1. Check for proper engine coolant level,
2. Check engine for proper operating temperature (approximately 91°C (195°F)). If engine does not reach 91°C (195°F), replace thermostat assembly.
3. With engine at normal operating temperature, check heater inlet and outlet hose temperature.
^ Heater inlet hose temperature should be at or near engine operating temperature.
^ Heater outlet hose temperature should be slightly cooler than the heater inlet hose.
^ If heater hose temperatures are incorrect, replace heater core.
4. Inspect plenum area (at base of windshield) for debris or anything that may cause airflow restriction.