Transmission Control (TC) Switch
WARNING: This page is about a different car, the 2005 Ford Pickup. However, it is still accessible from the selected car via links, so may be relevant.
The transmission control (TC) switch is a momentary contact switch that is located either on the end of the transmission control selector lever or the center console bezel of the floor shifter. Pushing the TC switch will either disengage or engage the overdrive function of the transmission. If the OVERDRIVE is disengaged, the word "OFF" will illuminate on the instrument cluster or in the message center.