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. Refer to the Parts Information..
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-. Refer to the Parts Information..
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 Parts Information. and use 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 Parts Information. and to using 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. Refer to the Parts Information..
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 CD CHANGER, REMOVING AND INSTALLING .
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. Refer to 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. Refer to Wiring Diagram.
Check the Auxiliary Heater Heating Element -Z35- function. Refer to AUXILIARY HEATER HEATING ELEMENT -Z35-, CHECKING .