RL V6-3474cc 3.5L (1998)
Oil Pressure Warning Lamp/Indicator: Description and Operation
How the Circuit Works
The low engine oil pressure indicator light works in two ways: it flashes continuously following a momentary loss of pressure, or it comes on and stays
on with a complete loss of engine oil pressure.
When the engine first starts, before its engine oil pressure rises above 4.3 psi, voltage is applied to the closed and grounded engine oil pressure switch,
and the light comes on to test the bulb.
With the engine running, voltage is applied at the WHT/BLU wire of the passenger's multiplex control unit. With normal engine oil pressure, the engine
oil pressure switch is open and the low engine oil pressure indicator light does not come on. If the engine oil pressure switch closes momentarily (more
than 0.5 second) but then opens again, the YEL/RED wire at the passenger's multiplex control unit will sense ground through the switch. The passenger's
multiplex control unit will then provide and remove ground for the low engine oil pressure indicator light through the YEL/RED wire. The light will
flash on and oft until you turn the ignition switch off. The flashing feature will not work until 30 seconds after initial voltage is applied to the WHT/BLU
wire of the engine oil pressure indicator flasher circuit. This delay keeps the low engine oil pressure indicator light from coming on during engine
warm-up.
If engine oil pressure falls below 10 psi and does not increase, the engine oil pressure switch will stay closed. The low engine oil pressure indicator light
will then come on and stay on.
