Toyota 4Runner 2001-06

Removal & Installation

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Fig. Exploded view of the front heater core, heater housing, evaporator housing and related components, Toyota calls the heater core the heater radiator-2001-02 Models

  1. Disarm the SRS system. For additional information, please refer to the following topic(s): -CHASSIS ELECTRICAL, Air Bag (Supplemental Restraint System)-.
    CAUTION
    Work must NOT be started until after 90 seconds from the time the ignition switch is turned to the LOCK position and the negative battery cable is disconnected from the battery. The SRS is equipped with a back-up power source so that if the work is started within the 90 seconds of disconnecting the negative terminal, the SRS may be deployed.

  2.  
  3. Drain the cooling system.
  4.  
  5. Discharge and recover the air conditioning system refrigerant.
  6.  
  7. Disconnect the refrigerant lines from the evaporator core. Discard the O-rings and plug the openings to prevent contamination.
  8.  
  9. Remove the glove compartment parts.
  10.  
  11. Remove the heater-to-register duct.
  12.  
  13. Disconnect the electrical connectors from the evaporator unit.
  14.  
  15. Remove the three screws and bolt to remove the evaporator unit.
  16.  
  17. Disconnect the heater hoses from the heater core pipes. Using pliers, grip the claw of clip and slide the clip along the hose.
  18.  
  19. Remove the instrument panel and reinforcement. For additional information, see the following topic: -Instrument Panel, Removal & Installation-.
  20.  
  21. Remove the defroster nozzle and heater to register duct.
  22.  
  23. Disconnect the connector from mode control servomotor.
  24.  
  25. If the vehicle is equipped with automatic A/C, disconnect the aspirator hose from room temperature sensor.
  26.  
  27. Disconnect the water valve control cable.
  28.  
  29. Remove the heater unit by removing the two mounting nuts.
  30.  
  31. Remove the following from the heater unit:
    1. Remove the water valve control cable.
    2.  
    3. Disconnect the electrical connecter and remove the servomotor.
    4.  
    5. If the vehicle is equipped with automatic A/C , pull the clamp off the engine coolant temperature sensor, and then remove the sensor.
    6.  
    7. Remove the clamp and plates that secure the heater core pipes.
    8.  

  32.  
  33. Remove the heater core from the heater unit.
  34.  
  35. Installation is the reverse order of removal.
  36.  
  37. Refill the cooling system to the correct level.
  38.  
  39. Evacuate and charge the air conditioning system.
  40.  
  41. Run the engine to normal operating temperatures; then, check the climate control operation and check for leaks.
  42.  



Click image to see an enlarged view

Fig. Heater core and related components-2003-06 models

  1. Disarm the SRS system. For additional information, please refer to the following topic(s): -CHASSIS ELECTRICAL, Air Bag (Supplemental Restraint System)-.
    CAUTION
    Work must NOT be started until after 90 seconds from the time the ignition switch is turned to the LOCK position and the negative battery cable is disconnected from the battery. The SRS is equipped with a back-up power source so that if the work is started within the 90 seconds of disconnecting the negative terminal, the SRS may be deployed.

  2.  
  3. Drain the cooling system.
  4.  
  5. Discharge and recover the air conditioning system refrigerant.
  6.  
  7. Disconnect the refrigerant lines from the evaporator core. Discard the O-rings and plug the openings to prevent contamination.
  8.  
  9. Using pliers, grip the claws of hose clip and slide the clip to disconnect the heater hoses from the heater core pipes.
  10.  
  11. Remove the instrument panel. For additional information, see the following topic: -Instrument Panel, Removal & Installation-.
  12.  
  13. Disconnect the five ECM wiring harnesses and remove the ECM.
  14.  
  15. Remove the air conditioning amplifier assembly.
  16.  
  17. Remove the all of the heater and air ducts, except the heater-to-register center duct.

    Click image to see an enlarged view

    Fig. The heater and air ducts must be removed-2003-05 Models

  18.  
  19. Remove the bolt and nut of the two No. 1 instrument panel brace mounting brackets.
  20.  
  21. Disconnect the steering column assembly wiring harness.
  22.  
  23. Remove the nuts and remove the steering column assembly.
  24.  
  25. Remove the six mounting bolts and eight nuts of the instrument panel reinforcement wiring harness. Release the 27 clamps and disconnect all of the wiring harness connectors.

    Click image to see an enlarged view

    Fig. Instrument panel reinforcement wiring harness

  26.  
  27. Remove the 12 mounting bolts and remove the instrument panel reinforcement.
  28.  
  29. Remove the heater-to-register center duct at this time.
  30.  
  31. Release the four claw fittings and remove the defroster lower nozzle assembly.
  32.  
  33. Disconnect the wiring harnesses and remove the air conditioner/heater unit.
  34.  
  35. Remove the clamp that secures the heater core pipes, and remove the heater core from the unit.

    Click image to see an enlarged view

    Fig. Remove the pipe clamp before removing the heater core from the air conditioner/heater unit-2003-05 Models

  36.  
  37. Installation is the reverse order of removal.
  38.  
  39. Refill the cooling system to the correct level.
  40.  
  41. Evacuate and charge the air conditioning system.
  42.  
  43. Run the engine to normal operating temperatures; then, check the climate control operation and check for leaks.
  44.  

 
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