Normal Operation
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 engine oil pressure switch is a normally closed switch that is hardwired to the instrument cluster through circuit 253 (DG/WH). When the oil pressure is within normal ranges, the engine oil pressure switch opens, interrupting the ground signal to the instrument cluster and turns the low oil pressure warning indicator off. When engine oil pressure is low, the engine oil pressure switch closes, supplying the ground to the instrument cluster, and illuminates the low oil pressure warning indicator.