Heater not hot

Hello, being full of engine coolant is only a tiny piece of the equation. The engine must reach proper operating temperature for the heater core to have sufficiently hot coolant circulating through it to create heat inside the vehicle. The climate control system has to be able to turn the doors inside the dash in order to create the proper all-hot blend of needed forced air from the climate control system. You could have a problem with the heater control valve. Hands on testing with the cooling system is needed.