Heater Core Case: Service and Repair

Heater Unit/Core Replacement

SRS components are located in this area. Review the SRS component locations Locations and precautions and procedures Service and Repair before doing repairs or service.

1. Do the battery terminal disconnection procedure.

2. Recover the refrigerant with a recovery/recycling/charging station A/C Refrigerant Recovery.

3. Disconnect the A/C lines from the evaporator core.

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.





5. When the engine is cool, drain the engine coolant from the radiator Service and Repair.

6. Slide the hose clamps (A) back, then disconnect the inlet heater hose (B) and the outlet heater hose (C) from the heater core. Note the layout of the hoses. Engine coolant will run out when the hoses are disconnected; drain it into a clean drip pan. Be sure not to let engine coolant spill on the electrical parts or the painted surfaces. If any coolant spills, rinse it off immediately.






7. Remove the mounting bolt and the heater valve as shown. Remove the mounting nut from the heater unit. Take care not to damage or bend the fuel lines and the brake lines, etc..






8. Remove the dashboard Dashboard Removal/Installation.

9. Remove the ECM/PCM ECM/PCM Replacement (A/T).

10. Disconnect the connectors (A) from the dashboard wire harness, the air mix control motor, the evaporator temperature sensor, the power transistor, the mode control motor, the blower motor, and the recirculation control motor, then detach the wire harness clips (B), the connector clips (C), and remove the wire harness (D), the heater duct (E), and the clip (F). Disconnect the drain hose (G), then remove the mounting bolts, the nut and the blower-heater unit (H).






11. Remove the self-tapping screws and the expansion valve cover (A). Carefully pull out the evaporator core (B) so you do not bend the inlet and outlet lines. Remove the self-tapping screws and the flange cover (C), then remove the grommet (D), and carefully pull out the heater core (E) so you do not bend the inlet and outlet lines.





12. Install the heater core and the evaporator core in the reverse order of removal.

13. 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 Service and Repair.
- Be sure to connect the drain hose securely.
- Adjust the heater valve cable Adjustments.
- Make sure that there is no engine coolant leakage.
- Make sure that there is no air leakage.

14. Do the battery terminal reconnection procedure.