Oil Pressure Telltale Indicator Lamp

The oil pressure telltale indicator lamp is switched to ground by the oil pressure switch. When the lamp is switched to ground, ignition voltage flows through the lamp, allowing it to come On. This indicates to the operator of the vehicle that the oil pressure has dropped below a specified limit.

The oil pressure indicator lamp will come On, for approximately 1 to 2 seconds at engine start up, until the oil pressure raises enough to open the oil pressure switch, for a bulb check.