Transmission Control Switch (TCS) and Transmission Control Indicator Lamp (TCIL)
WARNING: This page is about a different car, the 2009 Ford RV Cutaway, 2009 Ford Econoline, 2009 Ford E450 Super Duty, and 2009 Ford Cutaway. However, it is still accessible from the selected car via links, so may be relevant.
The Transmission Control Switch (TCS) is located inside the end of the selector lever. For vehicles equipped with a 4R70E/4R75E and a Torqshift® with a diesel engine, pushing the TCS will either disengage or engage the Overdrive (O/D) function of the transmission. When O/D is disengaged, the Transmission Control Indicator Lamp (TCIL) will illuminate T/C OFF on the Instrument Cluster (IC). Each time the ignition switch is cycled, the transmission will automatically provide O/D operation regardless of TCS position the last time the vehicle was running.