Your heater will blow cold air only.
It doesn't really blow it out it just warms the cold air.
it wont blow heat itll blow cold air
you need to replace your heater core
you are low on coolingliquid !
heater core possibly plugged and leaking
The front expansion valve is clogged.
No, not if it's on a heat setting. Most home thermostats have a "Fan" setting that will blow cold air if the attic is cold.
you may not have the heater water hoses plugged in
No! Thermostat.
replace front heater corefront and rear have independent heater cores
the heater core was stopped up just flushed it out ok now