A/C System Control and Regulation Components inside Passenger Compartment
A/C System Control and Regulation Components inside Passenger Compartment
1 Diagnostic socket
• Perform On Board Diagnostic (OBD) on A/C system Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
2 Instrument cluster
• With Outside Air Temperature Display (G106)
• Ambient temperature sent by front A/C control head Climatronic Control Module (J255) is displayed
• Check the temperature sensor measured values if the temperature display is incorrect vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
• The instrument cluster control module evaluates the Outside Air Temperature Sensor (G17) measured value and transmits it to the Climatronic Control Module (J255) front A/C control head via the Comfort databus system vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
3 Instrument panel vent with Left Center Air Outlet Sensor
• Potentiometer is installed in instrument panel vent.
4 Left Center Vent Motor (V110)
• With Left Center Vent Motor Position Sensor (G136)
5 Humidity Sensor (G355)
• Humidity Sensor (G355) is installed in area of interior mirror at windshield and connected to Roof Electronics Control Module (J528).
• Humidity Sensor (G355) determines temperature of windshield by means of infrared signal and humidity level by built-in condenser. Front A/C control head Climatronic Control Module (J255) uses measuring values to calculate temperature or humidity level at which windows start to fog up and alters setting vent temperature of air, vent direction of air and air flow rate. The sensor measured values are displayed in the measure value block for the Climatronic control module (J255) front A/C control head vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
6 Center Outlet Temperature Sensor (G191)
• Removing and installing, refer to => [ Center Outlet Temperature ] Service and Repair
7 Multi Media Interface (MMI)
• The functions selected on the Climatronic Control Module (J255) front A/C control head and various other A/C system functions are shown on the MMI display => Owner's Manual and => "Infotainment/MMI" Owner's Manual.
• The Setup button on the Climatronic Control Module (J255) front A/C control head can be used to call up various additional functions and adjust their settings => Owner's Manual.
• Depending on coding and adaptation of front Climatronic Control Module (J255), respective setting does not always appear on Multi Media Interface (MMI) display on vehicles as of model year 2007 when turning rotary temperature control with USA coding, indication appears only when rotary temperature control has been briefly pressed beforehand).
• From MY 2009, modified Climatronic Control Module (J255) A/C control heads without the Setup button were installed as a running change. On vehicles with these front A/C control heads, the screen in the "MMI" display will not switch to "A/C system" when the buttons and knobs on the front A/C control head are pressed. The selected A/C system functions are shown in the running display. Certain A/C system functions in these vehicles will be selected and activated with the rotary push buttons on the "MMI" unit => Owner's Manual and => "Infotainment/MMI" Owner's Manual.
• On vehicles that have a Climatronic Control Module (J255) front A/C control head without the Setup button, select the additional functions through the "Multi Media Interface (MMI) terminal" => Owner's Manual and => "Infotainment/MMI" Owner's Manual.
• Make sure the Climatronic Control Module (J255) front A/C control head is allocated correctly 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 Sunlight Photo Sensor (G107)
• Removing and installing, refer to => [ Sunlight Photo Sensor ] Service and Repair
9 Right Center Vent Motor (V111)
• With Right Center Vent Motor Position Sensor (G137)
• Removing and installing, refer to => [ Right Center Vent ]
10 Instrument panel vent with Right Center Air Outlet Sensor (G348)
• Potentiometer is installed in instrument panel vent
11 Air conditioner unit
• Different versions on vehicles with and without Rear A/C Control Head (Climatronic) (E265). Refer to => [ A/C Unit Components in Passenger Compartment ] A/C Unit Components in Passenger Compartment and => [ A/C Unit ] A/C Unit
• Air guide in air conditioner and in vehicle. Refer to => [ A/C Unit Components in Passenger Compartment ] A/C Unit Components in Passenger Compartment
• Components of heating & A/C unit in passenger compartment. Refer to => [ A/C Unit Components in Passenger Compartment ] A/C Unit Components in Passenger Compartment
• Removing and installing, refer to => [ A/C Unit ] A/C Unit
12 Evaporator drain hose
• Right front passenger side
• Checking, removing and installing, refer to => [ Condensate Drain Hose ] Description and Operation
13 Front A/C control head Climatronic Control Module (J255)
• Different versions without heated seats, heated seats without or with seat ventilation with an A/C button or a Setup button, etc.
• Removing and installing, refer to => [ Front A/C Control Head Climatronic Control Module ] Front A/C Control Head Climatronic Control Module
• Instrument Panel Interior Temperature Sensor (G56) is integrated in front A/C control head Climatronic Control Module (J255).
• Interior Temperature Sensor Fan (V42) is installed in front A/C control head Climatronic Control Module (J255), however it cannot be replaced individually. Refer to => [ Interior Temperature Fan ] Service and Repair.
• Also heed additional notes on A/C control head. Refer to => [ Front A/C Control Head Climatronic Control Module ] Front A/C Control Head Climatronic Control Module
• On Board Diagnostic (OBD) of front 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 in "Guided Fault Finding" function.
• Buttons and display fields are illuminated by Light Emitting Diodes (LED), cannot be replaced
• Two rotary knobs are attached. They can be removed and replaced separately.
• Front A/C control heads Climatronic Control Module (J255) with software number "026" installed in model year 2003: With these front A/C control heads Climatronic Control Module (J255), settings assigned to a specific person by fingerprint are lost when starting the vehicle via "One-touch memory ". Service installation of front A/C control heads Climatronic Control Module (J255) with this software number is therefore not permitted on vehicles with "one-touch memory".
• From model year 2009, the Climatronic Control Module (J255) front A/C control head with part number 4E0 820 043 from index "J" will be installed as a running change. On vehicles with these front A/C control heads, the screen in the " MMI" display will not switch to "A/C system" when the buttons and knobs on the front A/C control head are pressed. The selected A/C system functions are shown in the running display. Certain A/C system functions in these vehicles will be selected and activated with the rotary push buttons on the "MMI" unit Owner's Manual. The A/C button is available on these front A/C control heads instead of the Setup button.
• On vehicles that have a Climatronic Control Module (J255) front A/C control head without the Setup button, the additional functions are selected through the "Multi Media Interface (MMI) terminal" in the "A/C system" function Owner's Manual.
• Make sure the Climatronic Control Module (J255) front A/C control head is allocated correctly to the Information Electronics Control Module 1 (J794). There are different versions. If the allocation is incorrect, various A/C system functions cannot be displayed and selected in the MMI.
14 Interior Temperature Sensor Fan (V42)
• Installed in front A/C control head Climatronic Control Module (J255)
• Removing and installing blower. Refer to => [ Interior Temperature Fan ] Service and Repair
15 Instrument Panel Interior Temperature Sensor (006785-3211) (G56)
• Installed in front A/C control head Climatronic Control Module (J255), cannot be replaced individually
16 - Right Rear Footwell Heater (Z43)
• Removing and installing, refer to => [ Rear Footwell Heater ] Service and Repair
• Only installed on vehicles with Rear A/C Control Head (Climatronic) (E265) optional equipment
17 - Right Front Seat Temperature Sensor (G345) and Right Front Heated Seat (Z46)
• Seat heater and seat ventilation are not installed in all vehicles optional equipment
• Activation of seat heater and seat ventilation are displayed in measured value block of front A/C control head Climatronic Control Module (J255), checking Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
18 - Right Rear Warm/Cold Door Air Outlet Motor (V221)
• With Right Center Vent Motor Position Sensor (G352)
• Removing and installing, refer to => [ Right Rear Warm/Cold Door Air Outlet ]
• Only installed on vehicles with Rear A/C Control Head (Climatronic) (E265) (optional equipment)
• On vehicles without Rear A/C Control Head (Climatronic) (E265) without Right Rear Warm/Cold Door Air Outlet Motor (V221), doors for right side are moved via a joint shaft by Left Rear Warm/Cold Door Air Outlet Motor (V220). Refer to => [ A/C Unit Components in Passenger Compartment ] A/C Unit Components in Passenger Compartment.
• Connecting element between door and motor is "blue" colored
19 - Rear A/C Control Head (Climatronic) (E265)
• Not installed in all vehicles optional equipment
• Different versions with or without rear seat heater, rear seat heater with or without seat ventilation, allocation. .
• Removing and installing, refer to => [ Rear A/C Control Head, Climatronic ] and => [ Front A/C Control Head Climatronic Control Module ] Front A/C Control Head Climatronic Control Module
• Also heed additional notes on rear A/C control head. Refer to => [ Front A/C Control Head Climatronic Control Module ] Front A/C Control Head Climatronic Control Module and => [ Rear A/C Control Head, Climatronic ]
• On Board Diagnostic (OBD) of Rear A/C Control Head (Climatronic) (E265) is to be performed as described in Guided Fault Finding Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
• Check the adaptation of the Rear A/C Control Head (Climatronic) (E265) as described in Guided Fault Finding and change if necessary vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.
• Buttons and display fields are illuminated by Light Emitting Diodes (LED), cannot be replaced
• Two rotary knobs are attached. They can be removed and replaced separately. .
20 - Actuation of rear seat heater and seat ventilation
• Rear seat heater and seat ventilation are not installed in all vehicles optional equipment
• On vehicles without Rear A/C Control Head (Climatronic) (E265), rear seat heater is actuated via 2 rotary switches. Wiring diagrams, Troubleshooting & Component locations.
• Measuring values of Left Rear Heated Seat Temperature Sensor (G94) and Right Rear Heated Seat Temperature Sensor (G95) are displayed in measured value block of Rear A/C Control Head (Climatronic) (E265) Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding"
• Actuation of rear seat heater (Left Rear Seat Heating Element (Z10) to Right Rear Backrest Heating Element (Z13)) and seat ventilation is displayed in measured value block of Rear A/C Control Head (Climatronic) (E265), checking Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
21 - Left Rear Footwell Heater (Z42)
• Removing and installing, refer to=> [ Rear Footwell Heater ] Service and Repair
• Only installed on vehicles with Rear A/C Control Head (Climatronic) (E265)
22 - Left Front Seat Temperature Sensor (G344) and Left Front Heated Seat (Z45)
• Seat heater and seat ventilation not installed in all vehicles.
• Activation of seat heater and seat ventilation are displayed in measured value block of front A/C control head Climatronic Control Module (J255), checking Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.
• Servicing seat heater and seat ventilation.
23 - Left Rear Warm/Cold Door Air Outlet Motor (V220)
• With Right Center Vent Motor Position Sensor (G351)
• Removing and installing, refer to => [ Left Rear Warm/Cold Door Air Outlet Motor ]
• Only actuates doors for left side on vehicles with Rear A/C Control Head (Climatronic) (E265) optional equipment
• Connecting element between door and motor is "red" colored
• On vehicles without Rear A/C Control Head (Climatronic) (E265) without Right Rear Warm/Cold Door Air Outlet Motor (V221), doors for right side are also moved via a joint shaft by Left Rear Warm/Cold Door Air Outlet Motor (V220). Refer to => [ A/C Unit Components in Passenger Compartment ] A/C Unit Components in Passenger Compartment.
24 - Right Rear Center Console Temperature Sensor (G312)
• Only installed on vehicles with Rear A/C Control Head (Climatronic) (E265) optional equipment
• On vehicles without Right Rear Center Console Temperature Sensor (G312), mounting hole is sealed with plug
• Removing and installing, refer to => [ Left/Right Rear Center Console Temperature ] Service and Repair
25 - Left Rear Center Console Temperature Sensor (G311)
• Only installed on vehicles with Rear A/C Control Head (Climatronic) (E265)
• On vehicles without Left Rear Center Console Temperature Sensor (G311), mounting hole is sealed with plug
• Removing and installing, refer to => [ Left/Right Rear Center Console Temperature ] Service and Repair
26 - Evaporator drain hose
• Left side
• Checking, removing and installing. Refer to => [ Condensate Drain Hose ] Description and Operation
27 - Accelerator mechanism
• The compressor kick-down deactivation by the Climatronic Control Module (J255) front A/C control head (via the A/C Compressor Regulator Valve (N280)) is performed when there is a request from the engine control module. That data is exchanged via the CAN Bus system. The current condition is displayed in the measured value block for the Climatronic Control Module (J255) front A/C control head vehicle diagnosis, testing and information system VAS 5051 in the "Guided Fault Finding" function.