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Vehicles with manually controlled air conditioner > < Checking of heated rear windowZ1

A3 Mk2

Vehicles with automatically controlled air conditioner
Vehicles with automatically controlled air conditioner
Actuation by operating and display unit, Climatronic control unit -J255-
  Note
t  Situations preventing activation of the heated rear window (e.g. a short circuit in the connection to the rear window, an open circuit in the power supply to the operating and display unit, Climatronic control unit -J255-) are stored as faults in the corresponding control unit → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
t  If the voltage measured at the onboard supply control unit -J519- at terminal „30“ drops below a value stored in -J519-, the heated rear window is fully deactivated or the power is reduced to relieve the load on the alternator -C- → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
t  The heated rear window is only actuated by the onboard supply control unit -J519- when the engine is running. With the engine stopped, there is no feedback from -J519- and the LED in the button of the operating and display unit, Climatronic control unit -J255- goes out again shortly after actuation.
t  If the heated rear window has to be deactivated on account of undervoltage, the indicator lamp in the heated rear window switch in the operating and display unit, Climatronic control unit -J255- remains on. However if deactivation lasts longer than approx. 150 s, the operating and display unit, Climatronic control unit -J255- switches off the indicator lamp.
t  The measured value block of the operating and display unit, Climatronic control unit -J255- shows that the heated rear window -Z1- is being actuated or indicates why there is no actuation in spite of a corresponding request → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
t  Checking actuation of heated rear window operation is described in the air conditioner guided fault-finding → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
t  At ambient temperatures greater than 0 °C, the heated rear window is switched off automatically on completion of the operating period stored in the operating and display unit, Climatronic control unit -J255- (approx. 10 minutes) by -J255-.
t  On vehicles manufactured as of the start of production, the heated rear window is switched off by the onboard supply control unit -J519- after approx. 20 minutes at ambient temperatures below 0 °C. As of a later date (gradual introduction), vehicles were fitted with a -J519- which maintains actuation of the heated rear window -Z1- until the ignition is switched off (manual deactivation and reactivation possible at any time). If the temperature during a driving cycle rises above 0 °C, the heated rear window -Z1- is deactivated on completion of the operating period stored in the operating and display unit, Climatronic control unit -J255- (approx. 10 minutes).
t  As of Model Year 2010 a start/stop system will be available as an optional extra for this vehicle in conjunction with certain engines. On vehicles with a start/stop system, the heated rear window is deactivated whilst the stop function is active (to protect the battery -A-). The setting for actuation of the heated rear window -Z1- does however remain stored in the operating and display unit, Climatronic control unit -J255-. Once the engine has been re-started via the start function, the heated rear window is actuated again → "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
   

Vehicles with manually controlled air conditioner > < Checking of heated rear windowZ1