A/C Control Motor Block Diagram
A/C Control Motor Block Diagram
• In this vehicle various control motors (- A - through - N -) at the front A/C unit, under the instrument panel, at the rear A/C unit, or at the rear air distributor housing are adapted and activated via data lines. Different control motors (- A - through - N -) are connected in series to the Climatronic control module (J255) / rear A/C display control head (E265) via these data lines (LIN bus 1, LIN bus 2). If there is a malfunction in a control motor connected via this data line or in the wiring, this malfunction can result in various DTC memory entries with different malfunction types. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and.
• Depending on the vehicle equipment, varying numbers of control motors are connected to the Climatronic control module or the rear A/C display control head via the data line (LIN bus 2). If there is a malfunction in a control motor connected via this data line or in the wiring, this malfunction can result in various DTC memory entries with different malfunction types. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function and.
• 16 control motors are currently series-connected via the data line (LIN bus 1) to the Climatronic control module.
• In vehicles with a rear A/C display control head, 2 additional control motors (installed under the instrument panel) are series-connected via the data line (LIN bus 2) to the Climatronic control module. In vehicles without a rear A/C display control head, 6 additional control motors (installed under the instrument panel and on the rear air distributor housing) are series-connected via this data line to the Climatronic control module.
• In vehicles with a rear A/C display control head, the control motors installed on the rear A/C unit (currently 7 units) are connected via a data line to the rear A/C display control head. These control motors are activated in the same way as the control motors connected to the Climatronic control module (also via this series connection).
• The sequence of the control motors in the wiring is currently independent of the A/C unit version and the vehicle version (with steering on the left or right).
• In the basic setting function, adapt the control motors connected to the different data lines (LIN bus 1 and LIN bus 2 at the Climatronic control module and LIN bus at the rear A/C display control head) only when no malfunction with a cause other than a control motor that is not adapted or incorrectly adapted is stored in the Climatronic control module. In addition, adapt the control motors via the two data lines at the Climatronic control module one after the other. If you want to adapt the control motors connected to both data lines, check the event memory of the Climatronic control module after adaptation via a data line. Only conduct the adaptation operation via the second data line if the first operation was completed successfully. If a malfunction is present in one of the two data lines of the Climatronic control module, it may no longer be possible, depending on the malfunction, to clearly determine in which data line a malfunction occurred if the adaptation operation was performed via both data lines of the Climatronic control module in immediate succession. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
Depending on the operating state or the function of the Guided Fault Finding of the A/C unit during which a certain malfunction occurs or is present, the effect of the malfunction and the malfunction type stored in the event memory differ. Check using the Vehicle Diagnostic Tester in the "Guided Fault Finding" function.
• If there is a malfunction in the control motor sequence (two or more connectors at the control motors or the control motors were interchanged during installation).
- The function of the control motors with interchanged connectors may be OK until the next basic setting (addressing of the control motors). However, in the next basic setting, these control motors will be incorrectly adapted (addressed) and the activation of the control motors (and therefore the doors) will now be incorrect (incorrect allocation).
- If the connectors at the control motors are interchanged, these control motors are incorrectly adapted in the basic setting (addressed) and the activation of the control motors (and thus the doors) is incorrect (incorrect allocation). In the event interchanged connectors are suspected, check the wire connections between the control motors.
- Depending on the adjustment range for this control motor, an incorrect end stop is recognized during the basic setting and this is stored as a malfunction in the event memory, and the basic setting is terminated.
- If the wrong door moves, then the air flow direction is incorrect. This is not always recognized as a fault depending on the adjustment range of the control motor. Therefore, always label all connectors and control motors with the installation location before disconnecting them, and perform a basic setting after reconnecting them.
• If there is a malfunction in the normal operation of the A/C, then the following malfunction entries can result, depending on the type of malfunction.
- If there is a malfunction in the B+ or ground connection to a control motor, this control motor can no longer exchange information with the Climatronic control module (or rear A/C display control head) and this control motor is stored in the event memory.
- If there is a malfunction in the data line to a control motor (for example, an interruption in the harness connector to contact 2 of control motor - B -), this control motor and all control motors connected in series after this control motor (- C - through - N -) can no longer exchange information with the Climatronic control module (or the rear A/C display control head) and this control motor as well as all subsequently connected control motors are stored in the event memory.
- If a malfunction occurs in the control motor electronics (for example, in control motor - B -), control motor - B - may still be able to exchange information with the Climatronic control module (or the rear A/C display control head), depending on the type of malfunction. However, all motors connected after this one (- C - through - N -) are stored in the event memory.
• If there is a malfunction during the basic setting of the A/C, then the following malfunction entries can result, depending on the type of malfunction.
- If there is a malfunction in the B+ or ground connection to a control motor, (for example to control motor - B -), this control motor cannot exchange information with the Climatronic control module (or the rear A/C display control head) and is therefore not recognized during the basic setting. During the basic setting, all the control motors from the last control motor beginning with - N - are re-allocated and re-assigned; this control motor is no longer in sequence. The Climatronic control module (or the rear A/C display control head) detects that a control motor is missing and stores the first control motor in the series connection as missing. In addition, the malfunction "automatic addressing malfunctioning" is displayed and "upper or lower limit value exceeded" may be also displayed for certain control motors.
- If there is a malfunction in the data line to a control motor (for example, an open circuit in the harness connector to contact 2 of control motor - C -), this control motor and all control motors connected in series after this one can no longer exchange information with the Climatronic control module (or the rear A/C display control head), and these control motors are not recognized in the basic setting. During the basic setting, all the control motors from the last control motor beginning with - N - are re-allocated and re-assigned; these control motors are no longer in sequence. The Climatronic control module (or rear A/C display control head) detects that several control motors are missing (for example, only control motors - B - - A - are detected as incorrectly allocated and adapted). All other control motors are stored as missing in the event memory, and the malfunction "automatic addressing malfunctioning" is displayed.
- If a malfunction occurs in the control motor electronics or during the basic setting (for example, in control motor - C -), this control motor may still be able to exchange information with the Climatronic control module (or the rear A/C display control head) depending on the type of malfunction. However, no data can be exchanged with all control motors connected after this one (up to control motor - N -). The Climatronic control module (or rear A/C display control head) detects that several control motors are missing (for example, only control motors - C - through - A - are incorrectly allocated and adapted). All other control motors are stored as missing in the event memory and the malfunction "automatic addressing malfunctioning" is displayed.