Heater Unit/Core Replacement

2002 Honda Civic SiSECTION Heater Unit/Core Replacement
WARNING: This page is about a different car, the 2006 Honda Odyssey and 2005 Honda Odyssey. However, it is still accessible from the selected car via links, so may be relevant.

SRS components are located in this area. Review the SRS component locations (see COMPONENT LOCATION INDEX ), and the precautions and procedures (see PRECAUTIONS AND PROCEDURES ) before performing repairs or service.

  1. Make sure you have the anti-theft codes for the radio and the navigation system, then write down the XM radio channel presets.
  2. Make sure the ignition is OFF, then 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 in Fig 1.
    Fig 1: Turning Heater Valve Arm
    G03706363Courtesy of AMERICAN HONDA MOTOR CO., INC.
  5. When the engine is cool, drain the engine coolant from the radiator (see COOLANT REPLACEMENT ).
  6. Slide the hose clamps (A) back. Remove the nut and the water valve (B), then disconnect the inlet heater hose (C) and the outlet heater hose (D) 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 Inlet Heater Hose And Outlet Heater Hose From Heater Unit
    G03706364Courtesy of AMERICAN HONDA MOTOR CO., INC.
  7. 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 Mounting Nut From Heater Unit
    G03706365Courtesy of AMERICAN HONDA MOTOR CO., INC.
  8. Remove the dashboard (see DASHBOARD/STEERING HANGER BEAM REMOVAL/INSTALLATION ).
  9. Disconnect the connectors (A) from the blower motor and the power transistor, then remove the wire harness clips (B).
    Fig 4: Disconnecting Connectors From Blower Motor And Power Transistor
    G03706366Courtesy of AMERICAN HONDA MOTOR CO., INC.
  10. Disconnect the connectors (A) from the mode control motor and the recirculation control motor, then remove the wire harness clips (B) and the connector clip (C).
    Fig 5: Disconnecting Connectors From Mode Control Motor And Recirculation Control Motor
    G03706367Courtesy of AMERICAN HONDA MOTOR CO., INC.
  11. Disconnect the connectors (A) from the evaporator sensor and the air mix control motor, then remove the wire harness clips (B) and the wire harness (C).
    Fig 6: Disconnecting Connectors From Evaporator Sensor And Air Mix Control Motor
    G03706368Courtesy of AMERICAN HONDA MOTOR CO., INC.
  12. Remove the drain hose (A), then remove the nuts and the blower-heater unit (B).
    Fig 7: Removing Nuts And Blower-Heater Unit
    G03706369Courtesy of AMERICAN HONDA MOTOR CO., INC.
  13. Remove the self-tapping screws, the joint duct (A), and seal (B). Remove the self-tapping screws, then remove the passenger's heater outlet (C), and the heater core cover (D). Remove the self-tapping screws, the heater pipe brackets (E), the grommets (F), and carefully pull out the heater core (G) so you don't bend the inlet and outlet pipes.
    Fig 8: Removing Self-Tapping Screws, Joint Duct, And Seal
    G03706370Courtesy of AMERICAN HONDA MOTOR CO., INC.
  14. Install the heater core in the reverse order of removal.
  15. 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 COOLANT REPLACEMENT ).
    • 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  ).
    • Reset the power window control unit (see RESETTING THE POWER WINDOW CONTROL UNIT ).
    • Enter the anti-theft codes for the radio and the navigation system, then enter the customer's XM radio channel presets.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.