GF83.25-P-0003RC Automatic Heater, Function

GF83.25-P-0003RC Automatic Heater, Function
- except CODE (580) Automatic air conditioning
- except CODE (581) Comfort automatic air conditioning


Function requirements, general
^ Control functions: circuit 15 ON
^ Residual heat: circuit 15C or circuit 15R ON

Automatic heater in general
An automatic heater with 2-zone temperature control is installed, i.e. the automatic heater is equipped with a separate temperature control for the left and right halves of the vehicle. The blower control is performed in 1 zone and can be manually operated.

Regulation and control is performed by the automatic heater control and operating unit (N18).

The automatic heater is made up of the following subfunctions:
^ Residual engine heat utilization function sequence

Further partial functions are described in separate documents:
^ Heater circuit function
^ Ventilation system, function
^ Automatic heater control function

Additional function requirements for residual engine heat utilization
^ Circuit 15C or circuit 15R ON

Residual engine heat utilization function sequence
The residual engine heat utilization makes it possible to continue heating the vehicle for up to 30 min. For this purpose, the system utilizes the residual engine heat by pumping the still hot coolant through the heating system heat exchanger with the coolant circulation pump (M13) and blowing the heated air into the vehicle interior with the blower motor (A32m1).

The heater circulation pump is actuated by the control and operating unit. The control and operating unit transmits the switch on request for the heater circulation pump via the interior CAN to the driver SAM control unit with fuse and relay module (N10/1). The driver SAM control unit then actuates the heater circulation pump.
If the battery voltage is U < 11.7 volts when the residual engine heat utilization is switched on via the REST button, the LED flashes 3 times and the function is switched off. The function cannot be activated again until the battery voltage has increased to U > 11.7 V.
The blower air temperature control is dependent on the stored outside temperature and the specified temperature that has been selected.
The positions of the air flaps are saved before circuit 15 OFF and restored accordingly after circuit 15 ON.