Heater Unit/Core Replacement

SRS components are located in this area. Review the SRS component locations, and precautions and procedures in the SRS section before performing repairs or service. See AIR BAG RESTRAINT SYSTEMS .

1. Make sure you have the anti-theft code for the radio and the navigation system, then write down the frequencies for the radio's preset buttons.
2. Disconnect the negative cable from the battery.
3. From under the hood, open the cable clamp (A), then disconnect the heater valve cable (B) from the heater valve arm (C). Turn the heater valve arm to the fully opened position as shown.
   Fig 1: Disconnecting The Heater Valve Cable From The Heater Valve Arm (Fully Opened Position)

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
4. When the engine is cool, drain the engine coolant from the radiator.
5. Slide the hose clamps (A) back, then disconnect the inlet heater hose (B) and outlet heater hose (C) from the heater unit. Engine coolant will run out when the hoses are disconnected; drain it into a clean drip pan. Be sure not to let coolant spill on the electrical parts or the painted surfaces. If any coolant spills, rinse it off immediately.
   Fig 2: Disconnecting The Heater Hoses From The Heater Unit

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
6. Remove the mounting nut from the heater unit. Take care not to damage or bend the fuel lines, the brake lines, etc.
   Fig 3: Removing The Heater Unit Mounting Nut

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
7. Remove the dashboard (see INSTRUMENT PANELS article).
8. Remove the evaporator (see EVAPORATOR REMOVAL AND INSTALLATION ).
9. Remove the mounting bolts and the heater unit.
   Fig 4: Removing The Heater Unit

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
10. Remove the self-tapping screws, the mode control motor (A), and the linkage (B). Remove the selftapping screws and the brackets (C). Remove the self- tapping screws, then carefully separate the upper housing (D) from the lower housing (E). Be careful not to bend the inlet and outlet pipes when removing the heater core (F).
    Fig 5: Exploded View Of Heater Unit

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
11. Install the heater core in the reverse order of removal.
12. Install the heater unit in the reverse order of removal, and note these items:
    • Do not interchange the inlet and outlet heater hoses.
    • Install the hose clamps securely.
    • Refill the cooling system with engine coolant.
    • Adjust the heater valve cable (see HEATER VALVE CABLE ADJUSTMENT ).
    • Make sure there is no coolant leakage.
    • Make sure there is no air leakage.
    • Enter the anti-theft code for the radio and the navigation system, then enter the customer's radio station presets.
    • For '03 models: Perform the engine control module (ECM)/powertrain control module (PCM) idle learn procedure, and the power window control unit reset procedure (see COMPUTER RELEARN PROCEDURES ).