Electric Booster Heater Operation (Diesel equipped)
The electric booster heater ensures that the passenger compartment can be quickly warmed up when ambient temperatures are low. It is a heater element made up of ceramic resistors that is mounted in the climate control housing. It directly heats the airflow into the passenger compartment rapidly in the case of low ambient temperatures.
The current is switched via three electric booster heater relays located in the BJB. The electric booster heater power and ground is supplied via a plug-in connection.
The HVAC Control Module energizes the electric booster heater relays when the operating parameters have been met. The electric booster heater relays are activated or deactivated individually or together by signals from the HVAC Control Module as needed.
Electric booster heater operating parameters:
- Engine is running
- HVAC controls have been switched to the highest temperature setting
- Engine coolant temperature is below approximately 75°C (167°F)
- Ambient air temperature is below approximately 12°C (53.6°F)
- The duty cycle on the alternator must be below 65% to allow the electric booster heater to engage.
The electric booster heater is deactivated when an engine coolant temperature of approximately 85°C (185°F) or an ambient air temperature of approximately 15°C (59°F) is exceeded.
The electric booster heater is also deactivated when the alternator reaches max capacity, 100%, then it may be shut off as a load shedding strategy.