Left Side A/C System Control and Regulation Components
Left Side A/C System Control and Regulation Components
• Illustration shows the left side of the passenger compartment on a vehicle with left-side steering
1 Accelerator mechanism
• Kick down switch-off of compressor by the Climatronic Control Module (J255) A/C control head (via A/C Compressor Regulator Valve (N280)) is performed by request from Engine Control Module -ECM- (data is exchanged over the data bus system). The current status is displayed in the measured value block of the Climatronic Control Module (J255) A/C control head => Vehicle Diagnosis, Testing and Information System VAS 5051 in the "Guided Fault Finding" function.
2 Diagnostic socket
• Perform On Board Diagnostic (OBD) on A/C system => Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
3 Instrument panel vent, left
• Removing and installing instrument panel vents
4 Vent to left front door
5 Driver Information System (DIS) in instrument cluster
• With Outside Air Temperature Display (G106)
• The outside temperature is displayed at the Climatronic Control Module (J255) A/C control head in the measured value block => Vehicle Diagnosis, Testing and Information System VAS 5051.
• Check the temperature sensor measured values if the temperature display is incorrect => Vehicle Diagnosis, Testing and Information System VAS 5051.
• The measured value of the Outside Air Temperature Sensor (G17) is evaluated by Instrument Cluster Control Module (J285) and transmitted via Comfort CAN-Bus system to Climatronic Control Module (J255) A/C control head=> Vehicle Diagnosis, Testing and Information System VAS 5051.
6 Sunlight Photo Sensor (G107)
• Removing and installing => [ Sunlight Photo Sensor ] Service and Repair
• The solar radiation measured by Sunlight Photo Sensor (G107) and calculated by the Climatronic Control Module (J255) A/C control head is displayed in the measured value block => Vehicle Diagnosis, Testing and Information System VAS 5051.
7 Multi Media Interface (MMI) Display
• Different versions and operation; depends on the version of the MMI ("Infotainment" or "Basic") and vehicle equipment => Owner's Manual "Infotainment / MMI".
• The functions selected on the Climatronic Control Module (J255) A/C control head (and various other A/C system functions) are shown on the MMI display (different versions) => Owner's Manual and => "Infotainment/MMI" Owner's Manual.
• Various auxiliary A/C system functions can be selected and their settings modified via the Setup button on the Climatronic Control Module (J255)A/C control head or the rotary push-button on the MMI control unit (different versions) => Owner's Manual and => "Infotainment / MMI" Owner's Manual
• On vehicles with "Comfort" version A/C system from model year 2007, depending on coding and adaptation of front Climatronic Control Module (J255), the respective setting does not always appear on Multi Media Interface (MMI) display when turning the rotary temperature control (on the USA coding, the indication appears e.g. only when the rotary temperature control has been briefly pressed beforehand).
• From MY 2009, modified Climatronic Control Module (J255) A/C control heads are being installed as a running change=> [ (Item 11) A/C control head of A/C system ]. On vehicles with these A/C control heads, e.g. the screen in the "MMI" (Multi Media Interface) display will not switch to "A/C system" when the buttons and knobs on the A/C control head are pressed. The selected A/C system functions are shown in the running display (different versions) => Owner's Manual and => "Infotainment / MMI" Owner's Manual.
• On vehicles that have a Climatronic Control Module (J255) A/C control head "Comfort" version without the Setup button, select and activate the additional functions through the rotary push-button of the MMI control unit => Owner's Manual and => "Infotainment/MMI " Owner's Manual.
• Pay attention to the correct allocation of the Climatronic Control Module (J255) A/C control head, "Comfort" version to the Front Information Display Control Head Control Module (J523) / to the Information Electronics Control Module 1 (J794) (different versions). If the allocation is incorrect, various A/C system functions cannot be displayed and selected in the MMI.
8 Instrument panel vent, center
• With the Left Center Air Outlet Sensor (G347) and Right Center Air Outlet Sensor (G348).
- Using the two sensors, the Climatronic Control Module (J255) A/C control head detects whether the respective vent door is open or closed.
• Removing and installing instrument panel vents
• On vehicles with "Basic" version of Climatronic Control Module (J255), the temperature of the air outflow cannot be altered via the Multi Media Interface (MMI) => Operating instructions
• On vehicles with the "Comfort" version of the Climatronic Control Module (J255) A/C control head, the temperature of the air outflow cannot be altered via the Multi Media Interface (MMI) => Owner's Manual and => "Infotainment / MMI" Owner's Manual
9 A/C control head Climatronic Control Module (J255) of "Basic" version
• Different versions (for vehicle without or with seat heating, with left or right sided steering, temperature scale in °C or °F), assignment.
• Removing and installing => [ Climatronic Control Module A/C Control Head ] Climatronic Control Module A/C Control Head
• On Board Diagnostic (OBD) of A/C control head Climatronic Control Module (J255) is to be performed as described in Guided Fault Finding => Vehicle Diagnosis, Testing and Information System VAS 5051.
• Buttons and display fields are illuminated by Light Emitting Diodes (LED), cannot be replaced
10 Infrared sensor for temperature and sunlight
• The sensor determines the temperature and sunlight at the Climatronic (J255) A/C control head.
• The sensor is part of the "Basic" version of the Climatronic Control Module (J255) A/C control head and cannot be replaced individually.
• Check the measured value => Vehicle Diagnosis, Testing and Information System VAS 5051.
11 A/C control head Climatronic Control Module (J255) of "Comfort" A/C system
• Different versions (for vehicle without or with seat heating, with left or right-hand steering, with button A/C, Econ ON/OFF, or just with ON/OFF).
• Removing and installing => [ Climatronic Control Module A/C Control Head ] Climatronic Control Module A/C Control Head
• Instrument Panel Interior Temperature Sensor (G56) is integrated in A/C control head Climatronic Control Module (J255) (cannot be replaced individually).
• The "humidity sensor" is installed near the Temperature Sensor (G56) in the Climatronic Control Module (J255) A/C control head (cannot be replaced individually).
• Interior Temperature Sensor Fan (V42) is installed in A/C control head Climatronic Control Module (J255), however it cannot be replaced individually => [ Interior Temperature Sensor Fan ] Service and Repair.
• Also heed additional notes on the A/C control head => [ Climatronic Control Module A/C Control Head ] Climatronic Control Module A/C Control Head
• On Board Diagnostic (OBD) of A/C control head Climatronic Control Module (J255) is to be performed as described in Guided Fault Finding => Vehicle Diagnosis, Testing and Information System VAS 5051.
• Buttons and display fields are illuminated by Light Emitting Diodes (LED), cannot be replaced
• Starting with model year 2009, the Climatronic Control Module (J255) A/C control head "Comfort" version is gradually being installed, with part no. 4F1 820 043 as of index "AK" (vehicles with left-hand steering), or part no. 4F2 820 043 as of index "T" (vehicles with right-hand steering). On vehicles with these A/C control heads, e.g. the screen in the "MMI" (Multi Media Interface) display will not switch to "A/C system" when the buttons and knobs on the A/C control head are pressed. The selected A/C system functions are shown in the running display. For this A/C control head, the Setup button is replaced with the A/C button and the ECON ON /OFF button is replaced with the On/OFF button => Owner's Manual.
• On vehicles that have a Climatronic Control Module (J255) A/C control head "Comfort" version without the Setup button, select the additional A/C system functions using the rotary push-button of the MMI control unit (different versions) => Owner's Manual and => "Infotainment/MMI" Owner's Manual.
• Pay attention to the correct allocation of the Climatronic Control Module (J255) A/C control head, "Comfort" version, to the Front Information (J523) control head / to the Control Module for Information Electronics 1 (J794) (the (J255) control head in the "Comfort" with the Setup button are installed in vehicles with an Front Information (J523) control head, and the (J255) control head "Comfort" version without the Setup button are installed in vehicles with a Control Module for Information Electronics 1 (J794)) => Vehicle Diagnosis, Testing and Information System VAS 5051 in the "Guided Fault Finding" function. If the allocation is incorrect, various A/C system functions cannot be displayed and selected or selected in the MMI.
12 Interior Temperature Sensor Fan (V42) and Instrument Panel Interior Temperature Sensor (G56)
• Check the installation in the Climatronic Control Module (J255) A/C control head => Vehicle Diagnosis, Testing and Information System VAS 5051.
• Interior Temperature Sensor Fan (V42), removing and installing => [ Interior Temperature Sensor Fan ] Service and Repair.
• Instrument Panel Interior Temperature Sensor (G56) cannot be replaced individually
13 Left Front Seat Temperature Sensor (G344) and Left Front Heated Seat (Z45)
• Seat heater (and seat ventilation) is not installed on all vehicles (optional equipment, introduction of seat ventilation is not yet finalized)
• Activation of seat heater is displayed in measured value block of A/C control head Climatronic Control Module (J255), checking => Vehicle Diagnosis, Testing and Information System VAS 5051.
14 A/C unit (view from left)
• Different versions (with Climatronic Control Module (J255) A./C control head, "Basic" and "Comfort" versions vehicles with left or right-hand steering, vehicles with or without the Auxiliary Air Heater Heating Element (Z35)).
• Heating & A/C unit components => [ A/C Components ] A/C Components
• Air guide in air conditioner and in vehicle => [ Air Distribution in A/C and Air Intake Units, Block Diagram ] Air Distribution in A/C and Air Intake Units, Block Diagram
• Heating and A/C unit, removing and installing => [ A/C Unit ] A/C Unit
15 Condensate drain hose
• Left (driver side)
• Checking, removing and installing => [ Condensation Drain Hose ] Condensation Drain Hose
• 1 condensate drain hose each for driver's and front passenger's side.