Auxiliary Heater Element: Service and Repair

Auxiliary Heater Heating Element (Z35)

• Starting with MY 09, certain vehicles with a 6 cylinder TDI engine have an auxiliary air heater heating element installed depending on the emissions standard (running change depending on the engine). Refer to the Audi Sales Program and Electronic Parts Catalog.

• A reinforced auxiliary air heater heating element with a maximum output of 1500 W (instead of 1200 W) is installed for vehicles from MY 2013 with running changes. Make sure that the auxiliary air heater heating element is allocated correctly to the vehicle. Refer to Electronic Parts Catalog (ETKA).

• For more information regarding the auxiliary heater heating element, refer to => [ Auxiliary Heater Heating Element, Checking ] Testing and Inspection.

Removing

- Remove the glove compartment and instrument panel shell (the instrument panel cross-member does not get loosened or removed).

- Remove the heater core.

• Heater core with the A/C installed, refer to => [ Heater Core, Heating & A/C Unit Installed ] Heater Core, Heating & A/C Unit Installed.

• Heater core with the A/C removed, refer to => [ Heater Core, Heating & A/C Unit Removed ] Heater Core, Heating & A/C Unit Removed.

- Disconnect the connectors - A - and - B - (connector - B - with the wire connection to the auxiliary heater heating element).






- Loosen the auxiliary heater heating element ground connection - C - from the instrument panel cross-member; tightening torque: 9 Nm.

- Disconnect the connector - A - and the mounting points - B - for the A/C wiring harness - C -.






• The instrument panel cross-member is not shown in the illustration.

• Unlock the bracket on the mounting points - B - with a screwdriver - E -.

• The wiring harness - C - can only be removed downward together with the auxiliary heater heating element - D - (the wiring harness - C - is too stiff).

- Remove bolt - A -.






- Remove the auxiliary heater heating element - B - from the A/C unit in - direction of arrow -.

- Remove the wiring harness - C - from the A/C unit. When removing the auxiliary heater heating element - C - be careful not to pull or damage the wiring connections to the other electrical components on the A/C unit - C -.






Installing

Installation is carried out in the reverse order while noting the following:

- Attach the protective grille - A - to the auxiliary heater heating element - B -.






• The protective grille - A - prevents any electric components from short circuiting the heating elements - B - (which could happen, for example, via the instrument panel outlet on the auxiliary heater heating element.

- Install the rubber grommets - C - onto the pins - D -.

- Install the wiring harness - C - to the A/C unit as illustrated from the bottom toward the top. Be careful not to pull on or damage other electrical components on the A/C unit while installing the wiring harness - C -.






- Install the auxiliary heater heating element - B - pins and rubber grommets - C - into the A/C unit mounts - D -.






- Install the auxiliary heater heating element - B - opposite the - direction of arrow -.

- Install screw - A -.

- Install the wiring harness - C - and tighten the mounting points - B - on the A/C unit.






- Check the wiring harness - C - routing. It must installed so that it does not make any noise and so that it cannot come in contact with any moving components.

• Secure the wiring harness with additional cable ties and foam strips to keep it from moving or making noise.

- Secure the connector - B - to the A/C unit and then connect the connector- A -.






- Secure the auxiliary heater heating element ground connection - C - to the instrument panel cross-member; tightening torque: 9 Nm.

- Install the front heater core.

• Heater core with the A/C installed, refer to => [ Heater Core, Heating & A/C Unit Installed ] Heater Core, Heating & A/C Unit Installed.

• Heater core with the A/C removed, refer to => [ Heater Core, Heating & A/C Unit Removed ] Heater Core, Heating & A/C Unit Removed.

- Install the instrument panel shell and the glove compartment.

• After all the components are installed, except the glove compartment, check the auxiliary heater heating element control and function using the A/C and engine control module control diagnosis in Vehicle Diagnosis, Testing and Information System VAS 5051 in "Guided Fault Finding" function.

- Check DTC memory of Climatronic Control Module (and of the Rear A/C Display Control Head) and erase any DTCs displayed using the Vehicle Diagnosis, Testing and Information System VAS5051 in the "Guided Fault Finding" function.

- Install the glove compartment.