Car heater blowing cold air no fuses blown?

If your car heater is blowing cold air despite no blown fuses, it could be due to low coolant levels, which can prevent the heater core from receiving hot coolant. Another possibility is a malfunctioning thermostat that isn't allowing the engine to reach the proper operating temperature. Additionally, there may be an issue with the heater core itself, such as a blockage or leak. Checking coolant levels and inspecting the thermostat and heater core are good next steps for troubleshooting.