Rear Window Defogger, Checking

Rear Window Defogger, Checking

• There is a condition, which will not let the rear window defroster switch on. Short circuit in the rear window connector, open circuit in the voltage supply to the Climatronic control module (J255) etc. If this is stored as a fault in the Climatronic control module, refer to (VAS5051B) under "Guided Fault Finding".

• If voltage measured at the Vehicle Electrical System Control Module (J519) at terminal 30 falls below a value stored in the control module, then the rear window heater will be completely switched off (or output is decreased), and thus the load on Generator is relieved (activation duty cycle of 100% reduced to 90% by the Climatronic control module). Refer to (VAS5051B) under "Guided Fault Finding".

• If heated rear window must be switched off due to insufficient voltage, indicator lamp in heated rear window button on Climatronic control module remains switched on. However, if switch-off is to last longer than approximately 150 seconds, Climatronic control module switches off the indicator lamp.

• Climatronic control module measured value block indicates that heater of Heated Rear Window is switched on or why no activation is occurring despite a request. Check using (VAS5051B) under "Guided Fault Finding".

• The function test for the heated rear window is described in Guided Fault Finding, vehicle electrical system control module (J519). Refer to (VAS5051B) under "Guided Fault Finding". (Vehicle electrical system control module controls the heated rear window (Z1) ).

• The heated rear window stays switched on at outside temperatures up to 0°C until ignition is switched off (heated rear window can be switched manually at anytime). If temperature becomes greater than 0 °C during a driving period, the heated rear window is switched off after operating time stored in Climatronic control module has elapsed (approximately 10 minutes).

• Heated rear window may be switched off automatically by the Climatronic control module at outside temperatures greater than 0 °C after the operating time (approximately 10 minutes) stored in control head has elapsed (time of activation depends on coding and version of control head). Check using (VAS5051B) under "Guided Fault Finding".