Oil Pressure/Choke Indicator

If oil pressure less that 5 psi, a sending unit on the engine will close, completing indicator light ground circuit. Oil pressure light should come on when ignition is on and engine is not running.

Some models also have a choke indicator circuit using the same warning light as the oil pressure indicator. These models have an electrically heated choke. Lamp will light if choke heater or choke heater fuse fails and/or when ignition switch is in "RUN" position. On Ciera V6 models, indicator is grounded through choke heater. After engine starts and oil pressure builds up, oil pressure switch closes. Battery voltage is supplied to both the choke heater and the side of bulb near ground. With battery voltage at both sides of bulb, it goes out.

On V8 models, the oil pressure/choke indicator is grounded through the oil pressure switch. This switch opens when normal oil pressure builds up. The indicator then goes out.