Heating and ventilation system elements — removal and installation (BMW 3 Series E46)

Without air conditioning

Heating and ventilation control panel

1. Disconnect the negative cable from the battery.

2. Remove the audio system as described in Chapter 12.

3. Pull the handles away from the controls on the panel.

4. Remove the screws and detach the front panel from the ventilation and heating system control panel (Fig. 10.4).



5. Unscrew the four screws securing the panel frame, release the panel from the clips, press the panel inward and remove the frame from the opening (Fig. 10.5).



6. Disconnect the electrical connectors and unhook the cables from the controls. Mark the position of each cable and its routing to avoid errors during assembly.

7. Install the panel in reverse order. Route and connect the cables in accordance with the marks made during disassembly. Before finally securing the panel, check the operation of all controls

Heating and ventilation control cables

8. Remove the heating and ventilation control panel as described in paragraphs 1-6 and disconnect the corresponding cable from the control.

9. On right-hand drive models, remove the screws, unclip and remove the driver's side lower fascia trim. On left-hand drive models, remove the glove box as described in Chapter 11, paragraph 27.

10. Follow the routing of the desired cable behind the front panel and disconnect the other end of the cable from the mixing chamber.

11. Install the new cable in the reverse order. Make sure that the cable is routed correctly and that it is not kinked or twisted. Check the operation of the appropriate control, then reinstall the control panel.

Heater radiator

12. At the rear of the engine compartment, remove the ventilation and heating system air inlet duct as follows.

• a) Turn the three cabin filter cover fasteners 90 counterclockwise and remove the cover. Remove the cabin filter.
• b) Unfasten the latches of the box for laying the wires and remove the wiring from the box (fig. 10.12, a).
• c) Unscrew the four screws securing the cabin filter housing and pull the housing out.
• d) Remove two screws (fig. 10.12, b) and pull the air duct up out of the engine compartment.
• d) If necessary, pull up the rubber seal in the left rear corner of the engine compartment, release the two clips and pull out the partition panel (fig. 10.12, in).

13. Unscrew the expansion tank cap to equalize the pressure in the cooling system with atmospheric pressure, then close the tank again.



14. Clamp both heater hoses as close to the engine bulkhead as possible to reduce fluid loss. Alternatively, drain the coolant.

15. Disconnect the heater hoses at the engine bulkhead (fig. 10.15).



16. Remove the front panel as described in Chapter 11.

17. Remove the temperature sensor from the heating system mixing chamber (fig. 10.17). Release the wiring harness from its fasteners.



18. Pull the air duct out of the mixing chamber on the passenger side. Unscrew the screw of the heater tube bracket and remove the bracket (fig. 10.18).



19. Release the fasteners and remove the heater radiator cap from the mixing chamber (fig. 10.19).





20. Remove the heater radiator tube fasteners, lift the tubes and pull the radiator out of the mixing chamber (fig. 10.20). Remove the sealing rings from the tubes.

Note: Do not turn the radiator upside down to avoid drinking the liquid. If liquid does spill, immediately soak it up with a rag and wipe the spilled area dry.

21. Installation is performed in the reverse order of removal. Replace all sealing rings. Finally, fill the cooling system with liquid.

Heater fan

22. Disconnect the negative battery cable. In the engine compartment, remove the HVAC air inlet duct (see item 12).

23. On a 6-cylinder engine, remove the plastic engine covers so that they do not interfere with fan removal.

24. On all models, remove the rubber seal, unscrew the four screws and remove the fan cover.



25. Remove the fan mounting screws and lower the fan. Disconnect the fan wiring as soon as possible.

26. Install the fan in the reverse order. Secure the fan in the mixing chamber and cover the chamber with a lid.

Fan resistor

27. In the engine compartment, remove the air inlet duct of the heating and ventilation system as indicated in paragraph 12.

28. On all models, remove the rubber seal, unscrew the four screws and remove the fan cover.

29. Unscrew the resistor mounting screw, disconnect the wiring from it and remove the resistor.

30. Installation is carried out in reverse order.

Heater radiator valve

31. The coolant valve to the heater is installed on the left mudguard in the engine compartment. On some models, an auxiliary pump is located next to the valve (fig. 10.31). Unscrew the expansion tank cap to equalize the pressure in the cooling system with atmospheric pressure, then screw the cap back on.



32. Remove the air cleaner (see chapter 4A).

33. Clamp both heater hoses as close to the valve as possible to minimize fluid loss.

34. Disconnect the electrical wiring from the valve.

35. Loosen the clamps and disconnect the hoses from the valve, then disconnect the valve from the body and remove it from the engine compartment.



36. The valve is installed in the reverse order.

With air conditioning

Control Panel

37. Pull the gearshift lever handle up sharply and remove it from the lever (manual transmission) or remove the selector lever (automatic transmission).

38. Remove the gear shift lever base trim (or selector). After this, disconnect the electrical connectors.

39. Pull out the small box under the heater control panel. Carefully pry the bottom edge of the box, starting from the corner (fig. 10.39). If you are removing the cup compartment, press lightly on the top wall of the box, push it back about 2 mm, then press down on the right and left edges of the box and pull it out of the front panel.



40. Remove the four screws securing the box frame and pull the frame out of the front panel (fig. 10.40). Disconnect any electrical connectors that are now accessible.



41. Press the rear of the heater control panel and remove it from the front panel (fig. 10.41).



42. Disconnect the now accessible electrical connectors.

43. Installation is carried out in reverse order.

Heater radiator

44. Take the vehicle to a specialized service station to discharge the air conditioning system.

45. Remove the front panel as described in Chapter 11.

46. Remove the system air inlet duct in the engine compartment as described in item 12.

47. Clamp the heater hoses as close to the engine bulkhead as possible to minimize fluid loss. Alternatively, drain the coolant.

48. Loosen the heater hose clamps on the engine bulkhead and disconnect the hoses.

49. Remove the bolts securing the air conditioner tubes to the engine bulkhead. The tube seals can be discarded - new ones will be required for assembly.

50. Unscrew the bolt securing the two air conditioning system pipes to the engine bulkhead and move the pipes to the side (fig. 10.50). The seals can be thrown away - new ones will be needed for assembly.



51. Remove the four screws from the engine bulkhead on the engine compartment side (see Fig. 12.7,a,b).

52. Remove the steering column (see chapter 10)

53. Loosen the bolts and remove all the mounting brackets of the air conditioning system mixing chamber, disconnect all electrical connectors and remove the chamber.

54. Prepare for a coolant leak and place a suitable container under the heater radiator pipes.

55. Perform the actions described in paragraphs 17-20.

56. Installation is performed in the reverse order of removal. Replace all sealing rings during assembly. Finally, fill the cooling system. Take the car to a specialized service station to have the air conditioner refilled.

Heater fan

57. Remove the air inlet duct of the passenger compartment ventilation system as described in step 12. On models with a 6-cylinder engine and left-hand drive, remove the cylinder head cover (see chapter 2A or 2B).

58. Remove the rubber sealing strip from the air duct inlet.

59. Pull up the left damper shaft lever and remove the damper (fig. 10.59).



60. Remove one screw, unfasten the latches and remove the front fan cover (fig. 10.60).



61. Remove the three screws and remove the right cover from the fan (fig. 10.61, a, b).





62. Disconnect the electrical connector of the fan motor, press the retainer with a long thin tool and remove the fan (fig. 10.62). Pull the fan out through the opening on the passenger side.



63. Installation is performed in the reverse order of removal. The mounting protrusion on the mixing chamber housing must fit into the rectangular opening in the fan housing (fig. 10.63).

Fan resistor

64. See paragraph 12, subheading Fan speed limiter.

Heater radiator valve

65 See paragraphs 31-36.