Seat Heating and Ventilation, Checking
Seat Heating and Ventilation, Checking
Components Which Participate In The Activation Of The Front Seat Heating And Ventilation
The Climatronic control module (J255) , sends the request to switch on the seat heating/seat ventilation via the data bus to the respective control module (the control module depends on the vehicle version and vehicle equipment level). Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and.
• In the case of vehicles without a memory seat/steering column adjustment control module (J136) and a front passenger memory seat control module (J521) , the vehicle electrical system control module (J519) activates the driver seat heating and front passenger seat heating. The Climatronic control module, first sends the request for seat heating activation via the data bus to the data bus on board diagnostic interface (J533) and then to the vehicle electrical system control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• In the case of vehicles with a memory seat/steering column adjustment control module and a front passenger memory seat control module, the memory seat/steering column adjustment control module activates the driver seat heating and the front passenger memory seat control module the front passenger seat heating. The Climatronic control module, first sends the request for seat heating activation via the data bus to the data bus on board diagnostic interface and then to the memory seat/steering column adjustment control module and the front passenger memory seat control module. If only a memory seat/steering column adjustment control module and no front passenger memory seat control module is installed in a vehicle, the memory seat/steering column adjustment control module activates the driver seat heating, and the front passenger seat heating is then activated by the vehicle electrical system control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• A memory seat/steering column adjustment control module and a front passenger memory seat control module are always installed in vehicles with seat ventilation. These control modules then activate the seat ventilation and seat heating. Activation is performed as in vehicles with only seat heating in which the memory seat/steering column adjustment control module and the front passenger memory seat control module are installed. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• A start-stop system is available for certain engines for this vehicle. In vehicles with a start-stop system, the seat heating and ventilation are switched off whenever the stop function is active (to protect the battery). The setting for seat heating (and seat ventilation) activation remains stored in the Climatronic control module. After the motor is started again by the start function, the seat heating (and ventilation) is switched on again. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• The set driver seat heating or seat ventilation stage can be stored in a key-dependent manner. The settings made prior to the ignition being switched off are applied during the next driving cycle. Refer to operating instructions.
• There is currently no automatic shut-off for the seat heater and seat ventilation for an unoccupied seat while driving, for vehicles without passenger occupant detection system for the front passenger seat and the rear seat. If the ignition is turned off and not turned on again within approximately 10 minutes, the adjustment for the activation of the seat heater and the seat ventilator turns off. Refer to the Owners Manual.
• Depending on the vehicle, after a certain amount of time (for example after 10 minutes), the set driver seat heating or seat ventilation stage automatically reduces. Refer to the Owners Manual.
• Seat heating and seat ventilation activation can differ, depending on the vehicle version.
• Depending on the version and equipment of the vehicle, the various information regarding seat heating and seat ventilation activation (the setting transmitted by the Climatronic control module, the target and actual temperature, etc.) is displayed in different measured value blocks in various control modules using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• If there is a condition, where the heating or ventilation of the driver or passenger seat cannot be switched on (for example due to a short circuit in the connection to a seat heater element or an interruption in the current supply to the respective control unit, etc.), this will be stored as a malfunction in the vehicle electrical system control module , in the memory seat/steering column adjustment control module or in front passenger memory seat control module (depending on the vehicle type and the vehicle equipment level). In this vehicle, information stating that the event memory in the relevant control module needs to be read out may not be sent via the data bus to the Climatronic control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function. In the event of a complaint regarding seat heating or seat ventilation, first check the event memory of the control modules activating the seat heating and seat ventilation.
• The function test of seat heating and seat ventilation activation is described in the Guided Fault Finding for each control module (vehicle electrical system control module, memory seat/steering column adjustment control module or front passenger memory seat control module, depending on the vehicle version and equipment). Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• If, for example, the voltage at terminal 30 measured at the vehicle electrical system control module falls below a value stored in the vehicle electrical system control module, the seat heating and seat ventilation output is reduced or switched off completely in order to reduce the load of the generator. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• The read measured value block function in the Guided Fault Finding of the Climatronic control module, displays which seat heating or seat ventilation setting has been selected. The seat heating and seat ventilation activation, the actual and target seat temperature, the actual current supplied to the seat heating, etc. are displayed as a function of the version and equipment of the vehicle in the read measured values function of the Guided Fault Finding of the relevant control module using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• Depending on the vehicle version, the front passenger seat heating and ventilation can switch off after a certain period of time when it is detected that the seat is not occupied (deactivation via the passenger occupant detection system is not planned for the start of production, introduction not yet finalized). Refer to Operating instructions.
• There are different versions of the Climatronic control module. Refer to Electronic Parts Catalog. The different versions can be recognized, for example, by the symbols on the buttons - A - (for vehicles equipped with seat heating) and - B - (vehicles with seat heating / seat ventilation)
• When the seat heating is switched on, the function indicator lamps in the - A - buttons illuminate. When the seat ventilation is switched on, the function indicator lamps in the - B - buttons illuminate. Refer to Vehicle owner's manual.
• The seat heating and ventilation setting is adjusted by the Climatronic control module. The setting is transmitted to the relevant control module via the data bus. The target temperatures for the different seat heating and seat ventilation settings are stored in the relevant control modules. Depending on the version of the control module and the vehicle production period, the target temperature for the seat heating and seat ventilation can differ with the same setting on the Climatronic control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Components Which Participate In The Rear Seat Heating And Seat Ventilation Activation
Rear seat heating/seat ventilation activation depends on the version and equipment of the vehicle.
• For vehicles without the rear Climatronic A/C display control head (E265) the seat heater for the rear seats is adjusted via the left rear heated seat regulating switch (E128) , the left seat heating button (E653) or the left rear heated seat switch (E77) and the right rear heated seat regulating switch (E129) , the right seat heating button (E654) or the right rear heated seat switch (E78) (different descriptions depending on the version and date of manufacture of the vehicle). The activation of the left rear bench seat heating element (Z10) , the left rear backrest heating element (Z11) , the right rear bench seat heating element (Z12) and the right rear backrest heating element (Z13) is carried out by the rear seat heating control module (J786) or by the seat heating control module (J882) (different descriptions depending on the version and date of manufacture of the vehicle). This control module is currently not OBD-capable. However, activation only occurs when the vehicle electrical system control module (J519) provides the corresponding release. Check using the (Vehicle diagnostic tester) in the "Guided Fault Finding" function and.
In the case of vehicles with a rear A/C display control head, the rear seat heating and rear seat ventilation are set via the rear A/C display control head. The rear A/C display control head then activates the rear seat heating and rear seat ventilation as a function of the vehicle equipment and version.
• In vehicles without a left rear seat adjustment control module (J876) and a right rear seat adjustment control module (J877) , the rear A/C display control head activates the rear seat heating. The rear seat heating is activated by the rear A/C display control head if the vehicle electrical system control module does not receive a condition prohibiting seat heating activation. The vehicle electrical system control module first sends the request via the data bus to the data bus on board diagnostic interface and then via the Climatronic control module to the rear A/C display control head. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• In vehicles with a left rear seat adjustment control module and a right rear seat adjustment control module, the rear A/C display control head does not directly activate the rear seat heating and rear seat ventilation. In this case, activation is performed by the left rear seat adjustment control module and the right rear seat adjustment control module. The rear A/C display control head sends the seat heating and seat ventilation activation request to the Climatronic control module. It first sends the request via the data bus to the data bus on board diagnostic interface. The request is then relayed to the left rear seat adjustment control module and the right rear seat adjustment control module. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• A left rear seat adjustment control module and a right rear seat adjustment control module are always installed in vehicles with seat ventilation. These control modules then activate the seat heating and seat ventilation. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• A start-stop system is available for certain engines of this vehicle. In vehicles with a start-stop system, the seat heating and ventilation are switched off whenever the stop function is active (to protect the battery). The setting for seat heating (and seat ventilation) activation remains stored in the rear A/C display control head. After the engine is started again by the Start function, seat heating and ventilation is switched on again. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• Seat heating and seat ventilation activation can differ, depending on the vehicle version.
• Depending on the version and equipment of the vehicle, the various information regarding seat heating and seat ventilation activation (the setting transmitted by the rear A/C display control head, the target and actual temperature of the seat, etc.) is displayed in different measured value blocks in various control modules using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• In the event of a condition preventing heating or ventilation of the rear seat (for example short circuit in the connection to the seat heating element, open circuit in the voltage supply to the particular control module, etc.), this is stored as a malfunction in the rear A/C display control head, in the vehicle electrical system control module, in the Climatronic control module, in the data bus on board diagnostic interface, in the left rear seat adjustment control module or in the right rear seat adjustment control module (depending on the vehicle version and the vehicle equipment). In this vehicle, information stating that the event memory in the relevant control module needs to be read out may not be sent via the data bus to the rear A/C display control head. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function. In the event of a complaint regarding seat heating or seat ventilation, first check the event memory of the control modules activating the seat heating and seat ventilation.
• The function test of seat heating and seat ventilation activation is described in the Guided Fault Finding for the relevant control module (rear A/C display control head, left rear seat adjustment control module or right rear seat adjustment control module, depending on the vehicle version and equipment). Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• If, for example, the voltage at terminal 30 measured at the vehicle electrical system control module falls below a value stored in the vehicle electrical system control module, the seat heating and seat ventilation output is reduced or switched off completely in order to reduce the load of the generator. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• The read measured value block function in the Guided Fault Finding of the rear A/C display control head displays which seat heating or seat ventilation setting has been selected. The seat heating and seat ventilation activation, the actual and target seat temperature, the actual current supplied to the seat heating, etc. are displayed as a function of the version and equipment of the vehicle in the read measured values function of the Guided Fault Finding of the relevant control module using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• Depending on the vehicle version, the rear seat heating and ventilation can switch off after a certain period of time when it is detected that the seat is not occupied (deactivation via the passenger occupant detection system is not planned for the start of production, introduction not yet finalized). Refer to Operating instructions.
Note the following when operating the seat ventilation:
• In this vehicle heating is not automatically performed in the seat ventilation mode (activation and deactivation via the - B - button). Seat heating is only activated when seat heating is switched on via the - A - button. As a result, the following operating modes are possible (seat heating without seat ventilation, seat ventilation without seat heating, and seat heating with seat ventilation). Refer to Operating instructions.
• Activation of the seat blower fan and seat backrest blower fan (for example 1 blower fan in the backrest and 1 in the seat surface of each seat) depends on the selected seat ventilation setting (approximately 40% of maximum output at setting 1 and approximately 85% at setting 3). Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the arrangement of the components in the seat).
• Seat heating activation depends on the selected seat heating setting and the measured value of the temperature sensor in the seat surface. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the arrangement of the components in the seat).
• The selected setting for the driver seat heating and driver seat ventilation is saved when the ignition is switched off and the selected setting is allocated via the ignition key. After the ignition is switched on/the engine is started, the seat heating and seat ventilation are activated according to the last setting. Refer to Operating instructions.
• The selected setting for the front passenger seat and rear seat heating and ventilation is also stored when the ignition is switched off. However, if the ignition remains off for longer than approximately 10 minutes, the seat heating and seat ventilation are not reactivated after the ignition is switched on/the engine is started (the settings are erased). Refer to Operating instructions.
• When seat heating setting 3 is selected, the target temperature for the seat heating is reset after approximately 10 minutes (to approximately the value of setting 2). Depending on the version of the particular control module, the function indicator lamp for setting 3 in the - A - button can go out. Refer to Operating instructions.