Removing and installing heater and air conditioning unit — AUDI

🧭 Before you start

Fits: Audi A5 (8T, 2007–2016), Audi Q5 (8R, 2008–2017), Audi A5 Cabriolet (8F), Audi A4 B8 (8K, 2007–2015); platform code 83

• Opens: coolant, refrigerant (A/C)
• Special tools named: VAS 5051
• Renewed: any damaged components

Don't miss

• Use e.g. clean sealing plugs (B) (size 20) from engine bung setVAS 6122 for covering connections at JX1(A)
• The heat exchanger is designed for a certain coolant flow direction. Therefore it is important to connect the coolant hoses correctly.Bleed coolant circuit 19Cooling system/coolant; Draining and filling cooling system.
• In order not to damage the dash panel fascia, only place the dash panel on a clean workbench, covered e.g. with clean cardboard.
• The air duct to the left dash panel vent (A) is attached with a fastener or a bolt (B) to the dash panel cross member (C). This fastener or bolt can only be removed after taking out the dash panel fascia.
• With the exception of the fuse box (left-side), it is not necessary to unfasten any other relay and control unit brackets (left-side) from the dash panel cross member.

🔩 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. Move driver's and front passenger's seat as far to the rear as possible.
2. Switch off ignition.
3. Discharge refrigerant circuit Air conditioner with refrigerant R134a87Refrigerant circuit (Air conditioner with refrigerant R134a; Refrigerant circuit; Working with the air conditioner service station). [Note: Depending on the position of the service connection at the refrigerant line and the vehicle version, it may be necessary to remove the additional reinforcement for the body brace (left-side) to make it possible to connect the service coupling of the air conditioner service station (e.g. on the Audi Q5) Running gear, axles, steering40Suspension strut, upper links; Exploded view - suspension strut, upper links and Air conditioner with refrigerant R134a87Refrigerant circuit (Air conditioner with refrigerant R134a; Refrigerant circuit; Working with the air conditioner service station).]
4. ⚠ Risk of fatal injury if high-voltage components are damaged.Observe the following when working in the vicinity of high-voltage components or wiring:It is not permitted to use cutting or forming tools, other sharp-edged tools or heat sources such as welding, brazing, soldering, hot air or thermal bonding equipment.Before starting work, visually inspect the high-voltage components in the areas involved.Before working in the engine compartment, visually inspect the power and control electronics for electric driveJX1, electric drive motor V141, air conditioner compressor V470 and high-voltage wiring. Before working on the vehicle underbody, visually inspect the high-voltage wiring and covers. Before working on the rear section of the vehicle, visually inspect the high-voltage wiring and the electro-box with the maintenance connector for high-voltage system TW . Visually inspect all potential equalisation lines.Check the following when making the visual inspection:There must be no external damage on any component. The insulation of the high-voltage wiring and potential equalisation lines must not be damaged. There must be no unusual deformation of the high-voltage wiring. All high-voltage components must be identified by a red warning sticker. — De-energise high-voltage system Electrical system93De-energising high-voltage system. [Note: De-energising high-voltage system:Connect vehicle diagnostic testerSelect Guided Fault Finding modeUsing the Go to key, select the following menu items in successionFunction/component selectionBodyElectrical systemSelf-diagnosis compatible systems8C - Hybrid battery management -J8408C - Hybrid battery management, functions51 - De-energise high-voltage system (Rep. gr. 93)]
5. ⚠ High voltage can cause fatal injury.Danger of severe or fatal injuries from electric shock. The high-voltage system may only be de-energised by a suitably qualified person (Audi high-voltage technician). It must be definitely confirmed that the high-voltage system is de-energised. The system may only be de-energised using the vehicle diagnostic tester via "“Guided Fault Finding”". The qualified person (Audi high-voltage technician) confirms that the system is de-energised and uses the locking cap T40262 to ensure that the system cannot be re-energised. The ignition key and the maintenance connector for high-voltage system TW should then be stored in a safe place by the qualified person.The qualified person (Audi high-voltage technician) marks the vehicle by attaching the appropriate warning signs. — Remove rubber seal (A) and plenum chamber cover (B) (different versions) General body repairs, exterior50Bulkhead; Removing and installing plenum chamber cover.

6. After removing plenum chamber cover (B), visually inspect high-voltage components (D) (in this case power and control electronics for electric driveJX1) and high-voltage wires (E) and Electrical system93General warning instructions for work on the high-voltage system.
7. Detach earth connection from batteryAElectrical system27Battery; Disconnecting and connecting battery.
8. Unfasten power distributor (1) and set it down together with wiring towards windscreen Electrical system97Relay carriers, fuse carriers, electronics boxes; Overview of fitting locations - relay carriers, fuse carriers, electronics boxes.
9. Detach high-voltage wiring to JX1Electrical system93High-voltage wires; Overview of fitting locations - high-voltage wires.
10. Cover JX1 and corresponding wiring to prevent damage or contamination Electrical system93General warning instructions for work on the high-voltage system. [Note: Use e.g. clean sealing plugs (B) (size 20) from engine bung setVAS 6122 for covering connections at JX1(A)] [Note: Should it be necessary in order to be able to remove and install the expansion valve, remove the cowl panel trim (C)General body repairs, exterior50Bulkhead; Removing and installing plenum chamber cover.]
11. Detach earth connection from batteryAElectrical system27Battery; Disconnecting and connecting battery.
12. Remove plenum chamber cover and/or cowl panel trim (different versions) General body repairs, exterior50Bulkhead; Removing and installing plenum chamber cover.
13. Detach earth connection from batteryAElectrical system27Battery; Disconnecting and connecting battery. [Note: The earth connection of the batteryA is detached to prevent short circuits when the slave start socket (C) is detached and when the cable for the positive supply to the two relays for the auxiliary air heater element Z35(J) is detached.]
14. Remove cover for slave start socket (C).
15. On vehicles with auxiliary air heater element Z35, detach cable for positive supply to the two relays for Z35(J) from slave start socket (C)Electrical system97Relay carriers, fuse carriers, electronics boxes; Overview of fitting locations - relay carriers, fuse carriers, electronics boxes.
16. If fitted and if necessary, remove body brace (B) (e.g. on Audi A5 Coupé, not required e.g. on Audi Q5) Running gear, axles, steering40Suspension strut, upper links; Removing and installing body brace.
17. On vehicles with 6-cyl. TDI engine, remove plenum chamber partition panel (A)General body repairs, exterior50Bulkhead; Exploded view - bulkhead. [Note: On vehicles with a petrol engine or 4-cyl. TDI engine, the plenum chamber partition panel does not have to be unfastened or removed from the vehicle (there is sufficient space).On vehicles with a petrol engine or 4-cyl. TDI engine, the two coolant hoses to the heat exchanger are routed through the plenum chamber partition panel (A). On these vehicles, detach grommet at both coolant hoses and move partition panel to one side (this avoids having to open the coolant circuit).When unfastening the plenum chamber partition panel, pay attention to the vacuum line to the brake servo to avoid damaging it.]
18. Remove expansion valve . [Note: The air conditioning unit can also be removed and re-installed with the expansion valve attached. Here the removal and installation procedures are described with the expansion valve removed (more space and accessibility).Seal open pipe connections.To seal the open connections at the evaporator, use e.g. the caps of a replacement expansion valve.]
19. Detach retaining plate for expansion valve (A) from refrigerant lines (B) and (C) (to avoid losing it during removal).
20. Coat inside of grommet (D) with lubricant and remove support ring (E).
21. Detach grommet (D) towards passenger compartment from plenum chamber back wall (removed and installed together with air conditioning unit).
22. Release pressure in the coolant circuit by opening cap on coolant expansion tank 19Cooling system/coolant; Draining and filling cooling system.
23. Mark arrangement of coolant hoses (A) (supply from cylinder head) and (B) (return to coolant pump). [Note: The heat exchanger is designed for a certain coolant flow direction. Therefore it is important to connect the coolant hoses correctly.Bleed coolant circuit 19Cooling system/coolant; Draining and filling cooling system.]
24. Use hose clamps to pinch off the coolant hoses (A) and (B).
25. Cover area beneath connections for coolant hoses (A) and (B) e.g. with absorbent paper.
26. Detach coolant hoses (A) and (B) from connections to heat exchanger of air conditioning unit 19Cooling system/coolant.
27. Attach a section of tubing ((A) and (C)) to each of the two connections at the heat exchanger.
28. Place a container (B) underneath the other end of the hose (C).
29. Use a compressed-air gun (D) to carefully blow coolant out of heat exchanger (into container (B)) via hose (A).
30. Unfasten grommet (H) from plenum chamber back wall and detach from coolant pipes leading to heat exchanger.
31. Remove glove box General body repairs, interior68Shelves / trim panels; Removing and installing glove box.
32. Remove centre console (General body repairs, interior68Centre console; Removing and installing centre console) and dash panel (General body repairs, interior70Dash panel; Removing and installing dash panel). [Note: In order not to damage the dash panel fascia, only place the dash panel on a clean workbench, covered e.g. with clean cardboard.]
33. Remove air intake box .
34. Remove air ducts to dash panel vents (left and right). [Note: The air duct to the left dash panel vent (A) is attached with a fastener or a bolt (B) to the dash panel cross member (C). This fastener or bolt can only be removed after taking out the dash panel fascia.]
35. Remove air ducts to centre dash panel vent (C) and defroster vent (D).
36. Remove bolts (A) and (B).
37. Remove steering column Running gear, axles, steering48Steering column; Removing and installing steering column.
38. Unplug connector from brake light switchFBrake system45Sensors; Removing and installing brake light sensor.
39. Unfasten dash panel cross member (central tube) (E) from vehicle and air conditioning unit General body repairs, interior70Central tube for dash panel; Removing and installing central tube for dash panel. [Note: With the exception of the fuse box (left-side), it is not necessary to unfasten any other relay and control unit brackets (left-side) from the dash panel cross member.]
40. Remove air duct to vent in centre console (rear) (C) (only fitted on vehicles with "“deluxe”" air conditioner).
41. Unfasten air ducts to rear footwell vents (A) and (B) from intermediate piece (D) and remove intermediate piece (D).
42. On vehicles with an auxiliary air heater element Z35, unfasten earth connection (A) and unplug connector (B).
43. Detach the two condensation drain hoses from air conditioning unit .
44. Unfasten fuse holder (driver's side) on left side of dash panel cross member (central tube) (A) from dash panel cross member Electrical system97Relay carriers, fuse carriers, electronics boxes; Overview of fitting locations - relay carriers, fuse carriers, electronics boxes. [Note: As the dash panel cross member is only unfastened from the vehicle but not removed completely, the other relay/fuse carriers and connector points do not have to be detached from the dash panel cross member.]
45. Detach all electrical connections between dash panel cross member and vehicle on passenger's side (B).
46. Protect floor covering in area of centre tunnel with a sturdy mat (C) (and place loose covers on both seats if this has not already been done). [Note: It is not necessary to remove the dash panel cross member completely to remove the air conditioning unit; it is sufficient to unfasten it from the vehicle and the air conditioning unit, to swivel it to the rear on the right and then to set it down at the centre tunnel.]
47. Carefully unfasten the dash panel cross member from the vehicle and, making sure that no components are damaged by any connections which have not yet been unfastened, swivel it to the rear (arrow) on the passenger's side (B) so that the air conditioning unit can be removed to the right (arrow).
48. Detach vehicle wiring harness from air conditioning unit in area of dash panel cross member.
49. Carefully detach air conditioning unit slightly from vehicle, making sure that no components are damaged by any connections which have not yet been unfastened.
50. On vehicles with an auxiliary air heater element Z35, mark the position of the attachment points (B) (with cable ties at air conditioning unit) at the cable for the positive supply to the two relays for Z35(A) (e.g. with a suitable pen at cable).
51. Detach cable (A) from air conditioning unit.
52. Detach remaining fasteners of vehicle wiring harness (e.g. with cable ties) from air conditioning unit.
53. Remove air conditioning unit (A) towards passenger's side. [Note: Wiring harness for air conditioner is removed together with air conditioning unit.] [Note: Check all seals and grommets at the air conditioning unit for damage prior to installation and renew any damaged components.]
54. Insert air conditioning unit (A) with components removed together with air conditioning unit ("“air conditioner”" wiring harness, grommet at refrigerant lines to evaporator etc.) in vehicle.
55. Coat grommet (D) with lubricant and insert it in plenum chamber back wall.
56. Insert support ring (E) in grommet (D).
57. Install dash panel cross member (central tube) General body repairs, interior70Central tube for dash panel; Removing and installing central tube for dash panel.
58. Install retaining plate for expansion valve (A) at refrigerant lines (B) and (C).
59. Fit grommet (H) in plenum chamber back wall.
60. Check position of coolant and refrigerant lines in the two grommets and, if necessary, align air conditioning unit so that lines in grommets are not strained.

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
• Renewing desiccant bag for condenser, Caddy 2011 ►
• Removing and installing sill panel moulding
• Removing and installing aerial film for GSM/UMTS telephone in modular exterior mirror
• Removing and installing brake caliper piston, floating caliper disc brake 2FNR44
• Removing and installing combustion chamber with combustion tube · 1 torque figures