Auxiliary Heater Element: Service and Repair

Auxiliary Heater Heating Element (Z35)

• Vehicles with a TDI engine have an auxiliary heater heating element. Refer to the Electronic Parts Catalog (ETKA).

Removal

Danger of electrical short circuit.

Disconnect the battery before performing any work.

- Turn off all electric consumers.

- Switch off the ignition.

- Remove the key.

- Disconnect the battery.

- Remove the glove compartment..

- Remove the heater core for the heater and A/C unit. Refer to => [ Heater Core ] Service and Repair.

- Disconnect the connectors - A - and - B - and the wire connection from the auxiliary heater heating element.






- Loosen the auxiliary air heater heating element ground wire from the ground point - C - on the instrument panel crossmember (tightening specification: 9 +/-1 Nm).

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






• The heating and A/C unit is shown without the instrument panel crossmember.

• Unlock the brackets on the mounting points - B - with a screwdriver - E -, for example.

• The wiring harness - C - can only be removed downward together with the auxiliary air heater heating element - D -.

- Remove the bolt - A -.






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

- Loosen the wiring harness - C - from the heater and A/C unit.

- When removing the auxiliary heater heating element - C -, make sure that the wire connections to the other electrical components on the heater and A/C unit are not pulled or damaged while unscrewing the wiring harness - C -.






Installation

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

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






• The protective grille - A - prevents electrically conductive objects from short circuiting the heating elements - B - (which could happen, for example, via the instrument panel vents on the auxiliary heater heating element.

- Place the rubber grommets - C - on the pin - D -.

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






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






- Install the auxiliary heater heating element - B - in the heater and A/C unit opposite the - direction of arrow -.

- Tighten the bolt - A -.

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






- Check the wiring harness - C - routing. It must be 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.

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






- Tighten the auxiliary air heater heating element ground wire to the ground point - C - on the instrument panel crossmember (tightening specification: 9 Nm).

- Install the heater core.

- Install the glove compartment..

• After all components have been installed, except the glove compartment, check the auxiliary heater heating element activation and function using the "output diagnostic test mode" function of the A/C and engine control module using the Vehicle diagnostic tester in the "Guided Fault Finding" function.

- Check the DTC memory for the Climatronic control module (J255) and erase any faults if necessary using the Vehicle Diagnostic Tester in "Guided Fault Finding".