Ignition Switch On (Engine Off)
WARNING: This page is about a different car, the 2006 Dodge Grand Caravan, 2006 Dodge Caravan, and 2006 Chrysler Town & Country. However, it is still accessible from the selected car via links, so may be relevant.
When the ignition is turned on, the ECM activates the glow plug relay for a time period that is determined by engine coolant temperature, atmospheric temperature and battery voltage.