Transmission Control Switch (TCS)
WARNING: This page is about a different car, the 2004 Lincoln Navigator and 2004 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.
The transmission control switch (TCS) is a momentary contact switch that is located on the end of the column transmission control selector lever or on the floor shifter knob. Pushing the TCS will either disengage or engage the overdrive function of the automatic transmission. If the OVERDRIVE is disengaged, the word OFF will illuminate on the instrument panel.