Honda 79110-S30-A02 Heater Core

If the blower motor does not operate, check the blower motor fuse and replace it if necessary, inspect the wiring for loose, damaged, or corroded contacts and repair as needed, examine the blower motor switch and resistor pack for open circuits, and repair or replace them as required. If the heater blows cool air, verify the engine coolant level, topping off and bleeding the air from the cooling system if low, and check for leaks. Ensure the engine coolant operating temperature is within specification, and if it is below, investigate a potentially damaged or stuck thermostat. Additionally, check the heater control valve operation, ensuring the cable or vacuum hose is properly installed, and test the valve by moving the heater temperature control from hot to cold. With the engine at normal operating temperature and the control in the full hot position, feel the heater hoses; if one is hot and the other is much cooler, replace the control valve. If the heater steams the windshield when used, inspect for a loose cooling system hose clamp or leaking coolant hose near the engine firewall or under the dash, and repair as necessary. Look for a sweet odor and fluid dripping from the heater floor vents, which may indicate a failed heater core. Pressure test the cooling system with the heater set to fully warm and check for fluid leakage from the floor vents; if leakage is confirmed, remove and replace the heater core assembly, noting that on some vehicles, disassembly and removal of the dashboard may be required to access the heater core.