Dynasty L4-153 2.5L SOHC (1988)
Oil Pressure Warning Lamp/Indicator: Description and Operation
Many cars utilize a warning lamp on the instrument panel in place of the conventional dash indicating gauge to warn the driver when the oil pressure is
dangerously low. The warning lamp is wired in series with the ignition switch and the engine unit which is an oil pressure switch.
The oil pressure switch contains a diaphragm and a set of contacts. When the ignition switch is turned on, the warning lamp circuit is energized and the
circuit is completed through the closed contacts in the pressure switch. When the engine is started, build-up of oil pressure compresses the diaphragm,
opening the contacts, thereby breaking the circuit and putting out the lamp.
TROUBLESHOOTING
The oil pressure warning lamp should light when the ignition is turned on. If it does not light, disconnect the wire from the engine unit and ground the
wire to the frame or cylinder block. If the warning lamp still does not light with the ignition switch on, replace the bulb.
If the warning lamp lights when the wire is grounded to the frame or cylinder block, the engine unit should be checked for being loose or poorly
grounded. If the unit is found to be tight and properly grounded, it should be removed and a new one installed. (The presence of sealing compound on
the threads of the engine unit will cause a poor ground).
If the warning lamp remains lit when it normally should be out, replace the engine unit before proceeding further to determine the cause for a low
pressure indication.
The warning lamp will sometimes light or flicker when the engine is idling, even though the oil pressure is adequate. However, the lamp should go out
when the engine is speeded up. There is no cause for alarm in such cases; it simply means that the pressure switch is not calibrated precisely correct.
