Transmission Control Indicator Lamp (TCIL)
WARNING: This page is about a different car, the 2003 Ford Windstar. However, it is still accessible from the selected car via links, so may be relevant.
The Transmission Control Indicator Lamp (TCIL) is located in the instrument cluster and is labeled O/D OFF. It is illuminated in conjunction with the Transmission Control Switch (TCS). When a fault has been detected by the powertrain control module (PCM) the TCIL lamp will flash indicating a fault. The powertrain control module (PCM) communicates to the TCIL through the instrument cluster using the standard corporate protocol (SCP) communication network.