I have a 2005 mercury montego. Why doesn't my heater blow hot? on 2005 Mercury Montego

Just yesterday I replaced the water pump and thermostat.
The heat still blows cold. Now when I turn on the defrost I feel warm air as long as the vegicle is moving. But at an idle both defrost and heat blow cold.

Asked by for the 2005 Mercury Montego
This sounds more like the issue. A few months back I was hearing a clicking noise behind the glove box and thought it may have been some sort of vac leak to that door.
If thats the case whats the fix for it?
replace mode door,but fords have an issue with there heater box doors breaking best have it ck'd by a mech to be sure
1 more answer , 1 more comment
restricted heater core or still not full of coolant.
I checked the core with an air hose while I has it all apart, filled the coolant and bled the system. Still blowing cold