F 550 2WD Super Duty V10-6.8L VIN V (2005)
Transmission Shift Position Indicator Lamp: Description and Operation
TRANSMISSION CONTROL INDICATOR LAMP (TCIL)
The 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
the PCM Inputs Transmission Control Switch.
