Wait to Start Indicator (diesel only)
WARNING: This page is about a different car, the 2005 Ford RV Cutaway, 2005 Ford Econoline, and 2005 Ford E450 Super Duty. However, it is still accessible from the selected car via links, so may be relevant.
The PCM provides the ground for the wait to start indicator. The glow plugs and the wait to start indicator operate at the same time. The indicator illuminates until the PCM has provided time for the glow plugs to heat the combustion chamber. The PCM then sends a message over the communication network to the instrument cluster to turn off the indicator.