Transmission Control (TC) Switch
WARNING: This page is about a different car, the 2007 Ford Ranger. 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 on the transmission range selector lever. The transmission control indicator lamp (TCIL) is located in the instrument cluster. Pushing the TC switch will either disengage or engage the overdrive function of the transmission. When overdrive is disengaged, the TCIL will illuminate the word OFF. Each time the ignition switch is placed in the RUN position, the transmission will automatically provide overdrive operation regardless of TC switch position the last time the vehicle was running.