Removing and installing auxiliary air heater element Z35 — AUDI

🧭 Before you start

Fits: Audi A4 B9 (8W, 2015–)

• Renewed: it electronic parts catalogue

Don't miss

• On right-hand drive vehicles, move the driver's seat as far back as it will go.

🔩 Torque settings

Values can differ between engine variants — check the code stamped on your block.

ℹ️ Always cross-check the exact figure against your vehicle's factory manual before final tightening — a wrong torque can damage the engine. These values are extracted from workshop data and may not cover every variant or revision.

📋 Procedure

1. Switch on the ignition.
2. Move the front right seat (front passenger seat) as far back as it will go.
3. Switch off the ignition.
4. Remove the glove box General body repairs, interior68Shelves/storage compartments/covers; Removing and installing glove box. [Note: On right-hand drive vehicles, move the driver's seat as far back as it will go.]
5. Remove the right footwell vent (front passenger side) .

6. Remove the screw-type clip (A).
7. Unfasten the insulating mat (B) from the air intake box of the heater and air conditioning unit and detach.
8. If fitted, remove the air duct for glove box cooling .
9. Release the fastener (B) at the connector (A) to the auxiliary air heater element Z35 and unplug the connector (A).
10. Screw out the bolts (A).
11. ⚠ The heating surface of the auxiliary air heater element Z35(D) may be hot.If Z35 has been actuated prior to removal, do not grasp hold of the heating surface (D) of Z35. — Pull Z35(B) out of the heater and air conditioning unit mounting slot.
12. Check the heater and air conditioning unit for dirt by way of the mounting slot (C) (with cover (B) in position).
13. Check the foam seal (D) (if fitted) for damage and proper bonding by way of the mounting slot (C) (with cover (B) in position).
14. Check the foam seals (B, C) bonded (depending on version) to the heat exchanger (A) for damage and proper bonding by way of the mounting slot. [Note: The foam seals (B, C) are only fitted at the factory on a heat exchanger (A) for a "“High”" air conditioner. With a "“Low”" air conditioner (or heater with no air conditioner), there is no separation between the left and right side and between the rear and front in the air duct. The foam seals (B, C) are therefore not always fitted on heat exchangers in these heaters and air conditioning units. However, if they are bonded on, they must also be properly attached to the heat exchanger.If the foam seals (B) and (C) are damaged or not properly bonded on, they may work loose on inserting Z35 (with Z35) and problems may be encountered with regard to separation and regulation of the outflow temperature between the left and right side and between the rear and front during operation of the "“High”" air conditioner depending on the setting on the front air conditioner operating and display unit E87. Noise may also occur.If the foam seals (B) or (C) on a "“High”" air conditioner are not properly bonded on or are damaged, bond them firmly into position or replace them Electronic parts catalogue.If the foam seals (B) or (C) on a "“Low”" air conditioner (or heater with no air conditioner) are not properly bonded on, bond them firmly into position or remove them Electronic parts catalogue.The foam seal (B) on a "“High”" air conditioner provides separation between the left and right side at the heat exchanger (A). The purpose of the foam seal (C) is to separate the air duct for front and rear.Removal of the cover (B) for the heat exchanger on the right provides a better view of the mounting slot for J604 and the heat exchanger. To clean the heater and air conditioning unit, screw out the bolts (A) (tightening torque 1 Nm) and detach the cover (B) for the heat exchanger on the right.]
15. Check the foam seal (D) at the auxiliary air heater element Z35(B) for damage and proper bonding [Note: The foam seal (D) is only needed for a "“High”" air conditioner and is therefore only fitted at the factory on a Z35(B) for a "“High”" air conditioner. With a "“Low”" air conditioner (or heater with no air conditioner), there is no separation between the left and right side and between the rear and front in the air duct. A Z35(B) in these heater and air conditioning units is therefore not always provided with the foam seals(D). However, if it is bonded on, it must also be properly attached to Z35(B).If the foam seal (D) is damaged or not properly bonded on, it may work loose on inserting Z35 and problems may be encountered with regard to separation and regulation of the outflow temperature for rear and front during air conditioner operation depending on the version and the setting on E87. Noise may also occur.If the foam seal (D) on a "“High”" air conditioner is damaged or not properly bonded on, bond it firmly into position or replace it Electronic parts catalogue.If the foam seal (D) on a "“Low”" air conditioner (or heater with no air conditioner) is damaged or not properly bonded on, bond it firmly into position or remove it Electronic parts catalogue.]
16. Insert Z35(B) in the heater and air conditioning unit mounting slot.
17. Tighten the bolts (A) (tightening torque 1 Nm). — 1 Nm (0.7 lb-ft)
18. Plug in the connector (A) at Z35.
19. Re-install remaining components (removed earlier).
20. Perform basic setting and final control diagnosis for the heater and air conditioner "“Guided fault-finding”" mode. [Note: The control motors on this vehicle are equipped with electronics. A new control motor only learns its position at the heater and air conditioning unit in the course of basic setting and can then be actuated by the front air conditioner operating and display unit E87 (all control motors are identical at present) "“Guided fault-finding”" mode.During basic setting, the control motors are assigned and adapted in accordance with the series connection of the wiring. If the sequence is not as specified, the matching of the control motors and thus flap control will not be correct Overview of control motors of air conditioner.]
21. Interrogate the event memory of E87 and erase any faults displayed "“Guided fault-finding”" mode.
22. After installation, check the activation and operation of Z35 by way of J604 if applicable in "“Guided Fault Finding”" mode and Checking electric supplementary heater.

Other AUDI procedures

• Removing and installing toothed belt – Audi · 56 torque figures
• Removing engine – Audi A8 D3 · 41 torque figures
• Removing camshaft timing chain from camshafts – Audi A6/A7 C7 · 38 torque figures
• Installing engine – Audi A8 D4 · 36 torque figures
• Removing and installing camshaft timing chain · 29 torque figures
• Removing and installing selector lever lock solenoid N110 (vehicles up to 11.2005)
• Removing and installing shift unit (vehicles from 11.2005 onwards)
• Removing and installing storage well liner – Audi A6 C6
• 6-speed manual gearbox 0A3, four-wheel drive — Renewing oil seal for selector shaft with gearbox installed
• Removing and installing front exhaust pipe - vehicles with automatic gearbox