Oil Pressure Warning Lamp/Indicator: Description and Operation

The low oil pressure indicator light works in two ways: it flashes continuously following a momentary loss of oil pressure, or it comes on and stays on with a complete loss of oil pressure.

When the engine first starts, and before oil pressure rises above 4.3 psi, voltage is applied to the low oil pressure indicator light and the engine oil pressure switch to ground. This tests the bulb.

With the engine running, voltage is applied at the WHT/BLU wire of the integrated control unit. With normal oil pressure, the engine oil pressure switch is open, and the low oil pressure indicator does not go on. If the oil pressure switch closes momentarily (more than 0.5 second) but then opens again, the YEL/RED wire at the integrated control unit will sense ground through the switch. The integrated control unit will then provide and remove ground for the low oil pressure indicator light through the YEL/RED wire. The light will flash on and off until you turn the ignition switch off. The flashing feature will not work until 30 seconds after the initial voltage is applied to the WHT/BLU wire of the oil flasher unit. This delay keeps the light from coming on unnecessarily.

If engine oil pressure falls below 4.3 psi and does not increase, the oil pressure switch will stay closed. The low oil pressure indicator light will come on and stay on.