F 350 4WD Super Duty V10-6.8L VIN S (2004)
Transmission Shift Position Indicator Lamp: Description and Operation
TRANSMISSION CONTROL INDICATOR LAMP
The transmission control indicator lamp (TCIL) is an output signal from the PCM that controls the lamp on/off function depending on the engagement or
disengagement of overdrive. Refer to Transmission Control Switch in Hardware PCM Inputs.