Heater Unit/Core Replacement

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

1. Make sure you have the anti-theft code for the radio, then write down the frequencies for the radio's preset buttons.
2. Disconnect the negative cable from the battery.
3. Disconnect the suction and receiver lines from the evaporator core (see EVAPORATOR CORE REPLACEMENT ).
4. 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 Heater Valve Cable From Heater Valve Arm

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
5. When the engine is cool, drain the engine coolant from the radiator (see COOLING SYSTEM ).
6. Slide the hose clamps (A) back, then disconnect the inlet heater hose (B) and the outlet heater hose (C) from the heater core. 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 Heater Hoses From Heater Core

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
7. Remove the bolt and the heater valve, then remove the mounting nut from the heater unit. Take care not to damage or bend the fuel lines and the brake lines, etc.
   Fig 3: Removing Heater Valve & Removing Mounting Nut From Heater Unit

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
8. Remove the dashboard. See INTERIOR TRIM .
9. Disconnect the connectors (A) from the blower motor, the recirculation control motor, the mode control motor, and the power transistor, then remove the wire harness clips (B) and the connector (C). Remove the self-tapping screws and the bracket (D).
   Fig 4: Disconnecting Connectors, Removing The Wire Harness Clips, The Connector And The Bracket

   Courtesy of AMERICAN HONDA MOTOR CO., INC.
10. Disconnect the connectors (A) from the evaporator temperature sensor and the air mix control motor, then remove the wire harness clips (B) and the connector (C). Remove the self-tapping screw and the cover (D). Disconnect the heater valve cable (E).
    Fig 5: Disconnecting Connectors, Removing The Wire Harness Clips, The Connector And The Cover

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
11. Remove the mounting bolts, the mounting nuts, and the heater unit.
    Fig 6: Removing Heater Unit

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
12. Remove the self-tapping screws and the expansion valve cover (A). Carefully pull out the evaporator core (B) so you don't bend the inlet and outlet pipes. Remove the grommet (C), then remove the self-tapping screws and the flange cover (D). Remove the self-tapping screws and the pipe cover (E), then carefully pull out the heater core (F) so you don't bend the inlet and outlet pipes.
    Fig 7: Removing Heater Unit Components

    Courtesy of AMERICAN HONDA MOTOR CO., INC.
13. Install the heater core and the evaporator core in the reverse order of removal.
14. Install the heater unit in the reverse order of removal, and note these items:
    • Do not interchange the inlet and outlet heater hoses, and install the hose clamps securely.
    • Refill the cooling system with engine coolant (see COOLING SYSTEM ).
    • Adjust the heater valve cable (see HEATER VALVE CABLE ADJUSTMENT ).
    • Make sure that there is no coolant leakage.
    • Make sure that there is no air leakage.
    • Refer to evaporator core replacement (see EVAPORATOR CORE REPLACEMENT ).
    • Do the engine control module (ECM) idle learn procedure (see ECM/PCM IDLE LEARN PROCEDURE ).
    • Enter the anti-theft code for the radio, then enter the customer's radio station presets.