repair on 1990 Ford F-350

How do you take a heater out and replace it with a new one?

Asked by for the 1990 Ford F-350
The "heater" is a vague term - which particular component are you looking to take out?
all of it to replace it with a completly new one.
The heater consists of many components. You have the radiator, the hoses, the thermostat, the heater core, the plenum case, the temperature blend doors, the vacuum controls, the air flow blend doors, the control head...

Maybe you could share what specific problem you are experiencing?