Transmission Fluid Temperature (TFT) Sensor
WARNING: This page is about a different car, the 2002 Mercury Villager. However, it is still accessible from the selected car via links, so may be relevant.
This sensor is part of the shift solenoid harness. The sensor is immersed in the transaxle fluid and is used by the TCM to help determine shift timing and feel. The sensor is a variable resistor, and the value of its resistance changes with temperature.