The heater in my Daewoo Matiz only blows out COLD air .Why.?

If the heater in your Daewoo Matiz is only blowing out cold air, it could be due to several reasons. Common causes include low coolant levels, a malfunctioning thermostat, or a clogged heater core. Additionally, there may be an issue with the heater control valve or a problem with the heating system's blower motor. Checking the coolant level and ensuring there are no leaks can be a good first step in diagnosing the issue.