Oil Pressure
WARNING: This page does not describe the selected car, but rather 6 other vehicles, including the 1999 Oldsmobile Bravada, 1999 GMC Sonoma, 1999 GMC Jimmy, 1999 GMC Envoy, and 1999 Chevrolet S10 Pickup. However, it is still accessible from the selected car via links, so may be relevant.
Gauge responds directly to resistance of oil pressure sending unit. As oil pressure increases, sending unit resistance increases. Instrument Panel Cluster (IPC) monitors circuit for low oil pressure condition to determine if CHECK GAUGES indicator should be illuminated.