check the coolant level, or, possible stuck thermostat.
How to replace the inside Spectra Heater Core on a 2000 dodge durango??
There isn't a water control valve.
it is a heater. heat. it blows heat. warm air
Follow the heater hoses from the engine. They will lead right to the heater core.
Most likely a replacement heater core
Because you don't have enough coolant in your radiator.
You should check the thermostat and the fuse for the heater.
have the heater core cehecked out
It is inside the HCAV housing under the dash.
if you have already replaced the thermostat ,try replacing the heating core . it's located under the passanger side dash . There are a number of other things to investigate before going to the major under-taking of the heater core. See "Related Questions" below for a comprehensive trouble-shooting guide to Taurus/Sable heating problems.
you need a new thermostat and possibly some anitfreeze
The temperature blend door may be at fault.