Temperature control, IHS and IHKS

Temperature control, IHS and IHKS

This functional description covers the temperature control of the integrated heater control IHS and the integrated heating / air conditioner control IHKS.

Brief description of components

Temperature dial

The temperature dial is used to set the desired nominal temperature. Turning the temperature dial upwards increases the nominal temperature.

Sensors

• Evaporator temperature sensor with IHKS
  The evaporator temperature sensor measures the outlet temperature of the air at the evaporator to prevent freezing over. The evaporator temperature sensor is directly connected to the IHKA control unit.
  
• Coolant pressure sensor with IHKS
  The coolant pressure sensor is fitted in the pressure line between the condenser and the evaporator. Depending on the sensor signal, the air-conditioning compressor is regulated by the IHKS control unit in the event of excessive refrigerant pressure. The junction box supplies the coolant pressure sensor with voltage. The data is evaluated in the junction box electronics. The prepared data is sent across the body CAN (K-CAN) to the IHKS control unit.
  

System functions

Temperature control, IHKS

The ventilation temperature is regulated by the mixing flap in the heater/air conditioner. The air-mass flow is guided through the evaporator. The air-mass flow is cooled and dried (when the air conditioning system is switched on). Subsequently, the mixing flap guides the air-mass flow (depending on the set desired temperature value) fully or partially over the heat exchanger for the heating system and the electrical auxiliary heater. Subsequently, the air flows mix once again. The air-mass flow is then guided via the air distribution flap into the vehicle interior.

The evaporator temperature is regulated with the help of the evaporator temperature sensor and the expansion valve. The evaporator temperature is adjusted to the specified nominal value of 2 °C. Lower temperature are not possible due to the danger of freezing over. The evaporator control is independent of the temperature control in the vehicle interior.

Temperature control IHS

The ventilation temperature is regulated by the mixing flap in the heater/air conditioner. The mixing flap guides the air-mass flow (depending on the set desired temperature value) fully or partially over the heat exchanger for the heating system and the electrical auxiliary heater. Subsequently, the air flows mix once again. The air-mass flow is then guided via the air distribution flap into the vehicle interior.

Notes for Service department

Observe the following information for service:

General information

The following general data is provided for servicing the IHS / IHKS:

Replacement of the electrical auxiliary heater

The electrical auxiliary heater can be replaced in service (the heater/air conditioner must be completely removed).

Coding and programming

• Coding
  When coding the vehicle-specific data, the following details (among others) are taken into account:
  
  • Engine variant (diesel engine or petrol engine)
    
  • Version of the control unit
    
• Programming
  Flash programming of IHS / IHKS control unit via the K-CAN is possible.
  

Car and Key Memory

Almost all functions of the Car and Key Memory are set in the vehicle itself (see Owner's Handbook at ”Personal Profile”: personal settings for a maximum of 3 remote controls via the display in the instrument cluster or the Central Information Display).

Country-specific versions

The temperature display can be switched to °C or °F using the on-board computer function.

No liability can be accepted for printing or other errors. Subject to changes of a technical nature