My car heater not blowing warm air aircon works fine
Check your engine coolant level. The anti-freeze/water mix that keeps your engine from overheating also provides heat to the interior of the car. As the coolant circulates, it gets warm in the engine and then cools off when it goes to the radiator. Part of the loop is a heater core (small radiator). When you want heat, a fan blows air through the heater core and into your heat ducts. Air conditioning has its own completely separate system, so it's not unusual that one would work while the other doesn't.