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Home >> Mercedes Benz >> 2021 >> Metris Van Cargo >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Climate Control System (1 Of 3) -- 447 Chassis >> Basic Knowledge >> Pre-Entry Climate Control, Function - GF83.40-S-2014TRB

Pre-Entry Climate Control, Function - GF83.40-S-2014TRB

Model 447.6/7 

With Code HH4 (THERMOTRONIC automatic climate control) 

Model 447.6/7 

With Code HH9 (Air conditioner, automatic heater control) 

G16502050Courtesy of MERCEDES-BENZ USA

Function requirements, general 

Pre-entry climate control in general 

The pre-entry climate control is intended to temporarily heat up the area of the driver seat when getting in or ventilate it and to pre-cool the air from the air vents. Which of the two functions is initiated depends on the interior temperature and specified temperature preconfigured on the air conditioning control and operating unit (front & rear AAC). If the interior temperature is at least 6°C over the configured specified temperature, the pre-cool function is active; if the interior temperature is at least 10°C below the set specified temperature, the "pre-heat" function is active.

IMPORTANT The interior air temperature sensor sends the signal "Interior temperature" to the blower with interior air temperature sensor. It sends the signal directly to the air conditioning control and operating unit (front & rear AAC).

Pre-entry climate control is initiated by unlocking the central locking (CL [ZV]) via radio frequency. The electronic ignition lock (EZS) control unit sends the status of the central locking via interior CAN to the air conditioning control and operating unit (front & rear AAC). If the corresponding function is active, the air conditioning control and operating unit (front & rear AAC) then initiates the pre-entry climate control. With the "Pre-entry climate control" function, cooling or heating is possible for a certain time and is stopped after this time has elapsed or when the engine is started. If the charge level for the starter battery is sufficient, the preentry climate control can be activated up to 2 times without having to restart the engine.

The pre-entry climate control function encompasses the following subfunctions:

Function sequence for pre-cooling 

The air conditioning control and operating unit (front & rear AAC) sends a request to the heater/air conditioning air recirculation unit via climate control LIN 1. It forwards the request to the blower regulator, which then actuates the blower motor.

IMPORTANT Detailed information on the individual measures is available in the following function description:

Function sequence for pre-heating (With Code H16 (Seat heater for driver)) 

The air conditioning control and operating unit (front & rear AAC) sends the request for seat heater via interior CAN to the signal acquisition and actuation module (SAM) control unit, which forwards the seat heater request to the driver seat heater/ventilation control unit via heater LIN. It actuates the driver seat cushion heater pad and the driver seat backrest heater pad directly.

  Overview of system components for climate control   GF83.40-S-9994TRB