Cabin Heater: Operation: Deactivation

For vehicles with a Manual Temperature Control system, the DCHA will deactivate if the:

• engine is turned off.
• coolant temperature reaches 83°C (181°F).
• heater runs longer than 76 minutes (for normal automatic controlled heating operation).
• heater reaches 5-minute timeout period (for once per ignition cycle operation).
• fuel tank has less than 1/8 of a tank of fuel.
• Power switch on the A/C - Heater Control Module is off.
• Blend Control on the A/C - Heater Control Module is set below 75% reheat. 5 detents

For vehicle's with a Automatic Temperature Control system, the DCHA will deactivate if the:

• engine speed drops below 500 RPM.
• engine is turned off.
• coolant temperature reaches 83°C (181°F).
• heater runs longer than 76 minutes.
• fuel tank has less than 1/8 of a tank of fuel.
• Power switch on the Automatic Temperature Control is off.
• Comfort level is attained as determined by the temperature setting on the Automatic Temperature Control.

When the heater is deactivated, the combustion stops and a run-down sequence begins. During the run-down sequence, the combustion air fan continues operation to cool down the heater. The fan is automatically switched off after the run-down sequence is complete. The run-down time and the combustion air fan speed depend on the heater operating condition at the time of deactivation. Run-down time is approximately 175 seconds when deactivated in full load operation and approximately 100 seconds when deactivated in part load operation.