Low Oil Pressure Warning Indicator (Escape, Mariner)
WARNING: This page is about a different car, the 2006 Mercury Mariner and 2006 Ford Escape. However, it is still accessible from the selected car via links, so may be relevant.
The low oil pressure warning indicator is hardwired to the engine oil pressure switch. When the ignition switch is in the RUN position with the engine off, the engine oil pressure switch closes and the low oil pressure warning indicator illuminates. After the engine is started and the oil pressure builds up, the engine oil pressure switch opens, removing the ground circuit to the instrument cluster and turns off the low oil pressure warning indicator.