[97Bird]

Welcome to the forum Missy79. Look at post #7 in the first page of the Tech help thread (first thread at the top of the Thunderbird forum). It describes how to replace a heater core. Usually when the heater core starts to leak you will get a film on the inside of the windshield when you turn on the defroster. Have your cooling system level checked and pressure tested before attemping to replace the heater core- to be sure that is the problem. The AC drain hose might have come off which would cause water (not antifreeze) to leak into passenger side floor. If you have automatic temp control, look at my post at the top of the second page of the Tech help thread to see how to run the self test of the system. You may have a blend door actuator that isn't closing the blend door. The blend door position determines if the airflow goes through the heater core (for hot air) or bypasses the heater core (for cold AC air). Good luck.