Vehicles With Automatically Regulated A/C System

Vehicles With Automatically Regulated A/C System

Climatronic Control Module (J255) activation

• If there is one condition present so that the rear window heating does not switch on, for example, a short circuit in the connection to the rear window or an interruption in the voltage supply to the Climatronic control module (J255) , then this will stored in the control module as a fault. Check using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• If the voltage on the Vehicle electrical system control module (J519) to terminal 30 falls below the valued stored, the rear window defroster will be switched off completely or the power reduced to relieve the load on the generator. Check using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• The rear window defogger is controlled by the vehicle electrical system control module only when the engine is running. If the engine is not running, there is no message from the vehicle electrical system control module and the LED in the button in the Climatronic control module display and control head will go out for the short period.

• If heated rear window must be switched off due to insufficient voltage, indicator lamp in heated rear window button on Climatronic Control Module (J255) remains switched on, however if switch-off is to last longer than approximately 150 seconds, Climatronic Control Module switches off the indicator lamp.

• Measuring value block of Climatronic Control Module (J255) indicates that Heated Rear Window (Z1) activation is switched on or why no activation is occurring despite a request. Check using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• Checking actuation of heated rear window operation is described in Guided Fault Finding for A/C system for air conditioner. Check using Vehicle diagnosis, testing and information system (VAS5051B) in "Guided Fault Finding" function.

• With outside temperatures greater than 0 °C the heated rear window is switched off automatically by Climatronic Control Module (J255) after the programmed operating time (approximately 10 minutes) in -Climatic control module has elapsed.

• With ambient temperatures less than 0 °C in vehicles which were built from beginning of production, heated rear window is switched off by Vehicle Electrical System Control Module (J519) after approximately 20 minutes. At a later point in time, Vehicle Electrical System Control Module are installed (running change in production) in which Heated Rear Window (Z1) activation remains switched on until ignition is switched off (it can be switched off and back on again manually at any time). If the temperature becomes greater than 0 °C during a driving period, switch-off of the Heated Rear Window (Z1) occurs after the operating time stored in the Climatronic Control Module (J255) has elapsed (approximately 10 minutes).