Fresh Air Blower Control Module -J126-, REMOVING AND INSTALLING: Notes
There are different versions of the replacement Fresh Air Blower Control Module -J126- (for example, versions -A- and -B-). Pay attention to the correct allocation .
From the start of production through MY 2012, version -A- was installed. From MY 2012, version -A- was gradually switched to version -B- (the time when the changeover took place depends on the vehicle version). Version -B- also has a seal -C-.
From MY 2012 (use depends on the vehicle version), a revised Fresh Air Blower Control Module -J126- -B- (and Fresh Air Blower -V2-, Climatronic Control Module -J255- A/C display and control head and A/C units with part number "8T_ 820 005") are gradually being used. The air intake housing, along with the Fresh Air Blower Control Module -J126- and the A/C unit was also revised. Be sure to use the correct version and allocation. Refer to the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
If the allocation or adaptation of the Climatronic Control Module -J255- to the Fresh Air Blower Control Module -J126- (with the part number 8K0 820 521 or 8T0 820 521) is not according to the specification, then the Fresh Air Blower -V2- is not regulated by the Fresh Air Blower Control Module -J126-. There may not always be an entry in the DTC memory even though the activation of the Fresh Air Blower -V2- is not OK. Make sure the Climatronic Control Module -J255- is adapted correctly. Refer to the Vehicle Diagnostic Tester in the "Guided Fault Finding " function.
There is a label -A- on the outside of the A/C unit with a part number -B- that tells which version is installed .
The part number -B- on the label -A- can be read, for example, when the CD changer is removed (depending on the vehicle equipment level). Refer to DVD/CD Changer .
When the ignition is turned on and the Fresh Air Blower -V2- activated, The Fresh Air Blower Control Module -J126- connects (for example with version -A-) "Positive" from terminal "4" of connector -C- to the terminal "1" of connector -B-. The Fresh Air Blower -V2- speed is regulated by Fresh Air Blower Control Module -J126- via the ground connection between terminal "2" of connector -B- and terminal "3" of connector -C- using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function and, refer to appropriate SYSTEM WIRING DIAGRAM.
As a running change in MY 2010, gasoline engines that can run on bioethanol (Flex Fuel vehicles) were introduced, which currently have an Auxiliary Heater Heating Element -Z35-. Refer to Auxiliary Heater Heating Element -Z35-, CHECKING .
Currently an Auxiliary Heater Heating Element -Z35- is also installed on vehicles with a high voltage system (hybrid vehicles) and a gasoline engine. Refer to Auxiliary Heater Heating Element -Z35-, CHECKING .
For vehicles with a gasoline engine, the electric auxiliary heater (the Auxiliary Heater Heating Element -Z35-) is activated by the Climatronic Control Module -J255- display and control head via the local Data Bus (activated via the same outlet and also via the Fresh Air Blower Control Module -J126-) on the Auxiliary Air Heater Control Module -J604-. Also check the Auxiliary Air Heater Control Module -J604- if there is a concern about the Fresh Air Blower Control Module -J126- or the Fresh Air Blower -V2- for these vehicles using the Vehicle Diagnostic Tester in the "Guided Fault Finding " function and, refer to appropriate SYSTEM WIRING DIAGRAM.
Check the Auxiliary Heater Heating Element -Z35- function. Refer to Auxiliary Heater Heating Element -Z35-, CHECKING .