Why would I not have heat from my 2003 Taurus

Taurus cooling systems suck, heater cores alwsys get clogged

More often than not the heater core is plugged, but the thermostat may also be stuck in the open position. Try flushing the system and replacing the thermastat.

Try running some vinegar through the system for a while ! About a 16oz or so ! Run it through the system for awhile ! Its not a quick fix ! CLR might work too , but it may be too much for the system ! The car may act as if is over heating ! Because the reservoir will over flo from time to time ! Just put distilled or spring water in your cooling system as long as its spring or summer ! But don,t forget to have the system flushed . Before you add coolant for the winter ! It may still appear to over heat ! By overflowing at the reservoir ! But do not worry its trying to back flushes its self ! If you can do a back flush , do it ! It will hurry the process , after you have run the vinegar through for a couple of months ! I let mine run it,s course naturally ! it took awhile , but after 2 winters without heat I now have heat in the winter .