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 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 (J255) , 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 (J136) and a Front passenger memory seat control module (J521) , 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 (J533) 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 driver seat heating, and 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 (J136) and a Front passenger memory seat control module (J521) 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).
• The set driver seat heating or seat ventilation level 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 the Owner's manual.
• In vehicles without a passenger occupant detection system for the front passenger seat and the rear seats, there is currently no automatic deactivation of seat heating and seat ventilation in an unoccupied seat within a driving period. If the ignition is switched off and not switched back on within approximately 10 minutes, the setting for the activation of seat heating and seat ventilation is erased. Refer to the Owner's manual.
• The set level for seat heating and seat ventilation can be automatically lowered by one level after expiration of a certain time period (for example, after 10 minutes) depending on the vehicle. Refer to the Owner's manual.
• The seat heating and seat ventilation setting is set on the Climatronic control module. This setting is transmitted via the data bus to the Vehicle electrical system control module (J519). The target temperatures for the different seat heating and seat ventilation settings are stored in the Vehicle electrical system control module. Depending on the version of the Vehicle electrical system control module, the target temperature for seat heating and seat ventilation can therefore differ with the same setting on the Climatronic control module Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function (for the Vehicle electrical system control module).
• 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 of the seat, etc.) is displayed in different measured value blocks in various control modules. Check 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 (J136) or in Passenger memory seat control module (J521) (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 Vehicle Diagnostic Tester in the "Guided Fault Finding" function. for each control module (Vehicle electrical system control module, memory seat/steering column adjustment control module (J136) or front passenger memory seat control module (J521) , depending on the vehicle version and equipment).
• 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 values" 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 seat heating, etc. are displayed as a function of the version and equipment of the vehicle in the "Read measured values" function of the relevant control module. Check 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 the Owner's manual.
• The Climatronic control module, is available in different versions. Refer to Electronic Parts Catalog (ETKA). The different versions can be recognized, for example, by the symbols on the buttons - 2, 3 - (for vehicles equipped with "seat heating") and - 1, 4 - (for vehicles with "seat heating/seat ventilation").
• When seat heating/seat ventilation is switched on, the function indicator lamps in the buttons illuminate. Refer to the Owner's's manual.
• The seat heating and ventilation setting is adjusted on 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 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.
• In vehicles without a Rear A/C display control head (E265) , the rear seat heating setting is adjusted via the Left rear heated seat regulating switch (E128) or Left rear heated seat switch (E77) and the Right rear heated seat regulating switch (E129) or Right rear heated seat switch (E78). The Left rear bench seat heating element (Z10) , Left rear backrest heating element (Z11) , Right rear bench seat heating element (Z12) and Right rear backrest heating element (Z13) are activated by the Rear seat heating control module (J786). 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.
• The seat ventilation option is offered at the start of production only for certain versions and only for vehicles with a rear A/C display control head (E265). Refer to the Owner's manual.
• 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 rear seat heating. The rear seat heating is activated by the Rear A/C display control head if the Vehicle electrical system control module (J519) 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 (J533) and then via the Climatronic control module (J255) , 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 (J876) and a Right rear seat adjustment control module (J877) , the Rear A/C display control head does not directly activate 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 (J255). It first sends the request via the data bus to the Data bus on board diagnostic interface (J533). 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 (J876) and a right rear seat adjustment control module (J877) are not always installed in vehicles with seat ventilation. If no Left rear seat adjustment control module/Right rear seat adjustment control module is installed, the Rear A/C display control head activates the right rear seat ventilation control module (J801) and the left rear seat ventilation control module (J802) directly via a data line. Depending on the vehicle equipment, these control modules then activate the fans and heating elements of the rear seat bench/backrest. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and (for the particular vehicle system).
• 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 (E265) , the target and actual temperature of the seat, etc.) is displayed in different measured values in various control modules. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• In the event of a condition preventing heating or ventilation of the rear seats (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 (E265) , in the vehicle electrical system control module (J519) , in the Climatronic control module (J255) , in the data bus on board diagnostic interface (J533) , in the left rear seat adjustment control module (J876) or in the right rear seat adjustment control module (J877) (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 (E265) , left rear seat adjustment control module (J876) or right rear seat adjustment control module (J877) , 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 (J519) 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 values" function in the Guided Fault Finding of the rear A/C display control head (E265) 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 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. Check 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 the 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 - 1, 4 - button). Seat heating is only activated when seat heating is switched on via the - 2, 3 - 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 the 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 (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 (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 the 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 the 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 buttons can go out. Refer to the Owner's manual.