What to you mean by "floor heat"? The heat blowing out the bottom vents?? If so have you set the heat to just come out the floor vents? Is it also coming out of any other then the floor vents? If so the Mode door maybe broken. From the Shop Manual
Defrost/Panel/Floor Mode Door Position
Airflow through the HVAC plenum is controlled by the defrost/panel/floor mode door actuator. The defrost/panel/floor mode door actuator contains a reversible electric motor and potentiometer. The potentiometer allows the HVAC control module to monitor the position of the defrost/panel/floor mode door. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the HVAC control module from the contact wiper indicates the position of the defrost/panel/floor mode door. The HVAC control module powers the actuator motor to move the defrost/panel/floor mode door to the desired position. The desired position is set by the vehicle occupants using the mode selector buttons.