BMW 64518398746 Heater Radiator

The blower motor may not operate due to a blown fuse, loose or damaged wiring, or issues with the switch and resistor pack, all of which should be checked and repaired as necessary. If the heater blows cool air, ensure the engine coolant level is adequate, and if low, top it off while bleeding the air from the cooling system and checking for leaks. Verify the engine coolant operating temperature and inspect the thermostat for damage if the temperature is below specification. Additionally, check the heater control valve for proper operation and installation of the cable or vacuum hose, moving the temperature control from hot to cold to confirm functionality. If one heater hose is hot and the other is cooler while the engine is at normal operating temperature, the control valve may need replacement. If the heater steams the windshield, inspect for loose hose clamps or leaking coolant hoses near the engine firewall or under the dash, and repair as needed. A sweet odor and fluid dripping from the heater floor vents may indicate a failed heater core, which should be pressure tested with the heater set to warm to check for leaks; if confirmed, the heater core assembly will need to be removed and replaced, noting that disassembly of the dashboard may be required for access.