Blower Motor: Service and Repair
Fresh Air Blower (V2)
• The fresh air blower as a replacement part is available in different versions, make sure of the correct application. Refer to Electronic Parts Catalog (ETKA).
• As a running change, the fresh air blower - A - has an additional foam sheathing - B - (as a noise insulation) from 08.2007. Refer to the Parts Catalog.
• As a running change in MY 2009, a fresh air blower - A - with a revised housing with an optimized motor and motor mount, is being used. With the use of the new fresh air blower, the foam jacket on the house - B - is discontinued because the larger motor mount has a new insulation mat (see - B - in the next illustration). Refer to Electronic Parts Catalog (ETKA).
• From MY 12 (depending on the version of the vehicle) revised fresh air blower control module (J126) , fresh air blower, Climatronic control module (J255) and A/C units are being used. Be sure to use the correct version and allocation. Refer to the Parts Catalog and the Vehicle diagnostic tester in "Guided Fault Finding".
• There is a label - A - on the outside of the A/C unit with a part - B - that tells which version is installed. Refer to the Parts Catalog.
• The part number - B - on the decal - A - can be read when the CD changer is removed (depending on the vehicle equipment level). Refer to Electronic Parts Catalog (ETKA).
• As a running change in MY 10, 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), Testing ] Testing and Inspection.
• Currently an auxiliary air heater heating element is installed for vehicles with a high voltage system (hybrid vehicles) and a gasoline engine. Refer to => [ Auxiliary Heater Heating Element (Z35), Testing ] Testing and Inspection.
• The activation of the auxiliary heater heating element occurs for vehicles with a gasoline engine from the Climatronic control module via the local Data bus (controlled using the same outlet and also using the fresh air blower control module (J126) ) on the auxiliary air heater control module (J604). Check the fresh air blower control module or the fresh air blower and also the auxiliary air heater control module when complaints arise for these vehicles. Refer to the Vehicle diagnostic tester in "Guided Fault Finding".
• From MY 12 (introduction depending on the vehicle version) a revised fresh air blower control module (and fresh air blower, Climatronic control module and A/C units with part number"8T_ 820 005") are being used. The air intake manifold, along with the fresh air blower control module and the A/C unit is also revised. Be sure to use the correct version and allocation. Refer to the Parts Catalog and the Vehicle diagnostic tester in "Guided Fault Finding".
• The fresh air blower control module does not control the fresh air blower if the Climatronic control module allocation or adaptation to fresh air blower module (part number 8K0 820 521 or 8T0 820 521) is not according to the specification. There may not always be an entry in the DTC memory even though the activation of the fresh air blower is not OK. Make sure the Climatronic control module adaptation is correct. Refer to the Parts Catalog and to the Vehicle diagnostic tester in "Guided Fault Finding".
• Make sure the auxiliary air heater heating element is working. Refer to => [ Auxiliary Heater Heating Element (Z35), Testing ] Testing and Inspection.
Removing
- Remove the screw clips - A - and remove the insulation mat - B -.
- Remove the fresh air blower control module (J126) (version - A -). Refer to => [ Fresh Air Blower Control Module (J126) ] Fresh Air Blower Control Module (J126).
• A revised fresh air blower control module (J126) - B - and fresh air blower (V2) are being installed as a running change (depending on the version of the vehicle) from MY 12. It is not always necessary to remove the fresh air blower control module in order to remove the fresh air blower on the revised version - B -.
- Loosen the locking mechanism - A - and turn the fresh air blower - B - housing in the direction of the arrow.
Do not grasp fan wheel of Fresh Air Blower, force against the fan wheel or shifting the balancing weights fastened to fan wheel may cause imbalance and then problems during operation.
Installing
Installation is carried out in the reverse order while observing the following.
- If the locking mechanism - A - breaks or can no longer hold, secure the fresh air blower - B - to the air intake housing with a screw - C -.
- Make sure the fresh air blower - B - fits securely in the air intake housing when installing it.
- Switch on the ignition.
- Check the Climatronic control module (J255) DTC memory and erase any displayed malfunctions if necessary using the Vehicle diagnostic tester in "Guided Fault Finding".
- To check the function, perform an output Diagnostic Test Mode (DTM) on the A/C system using the Vehicle diagnostic tester in "Guided Fault Finding".