Oil Pressure Gauge & Sending Unit Test

With a voltmeter, check for battery voltage at load side of fuse No. 18. See Figure . If battery voltage is present, go to step 3). If voltage is not present, go to next step.
With a voltmeter, check for battery voltage at feed side of fuse No. 18. If battery voltage is present, replace fuse and retest circuit. If voltage is not present, repair wiring to fuse panel and retest.
Partially remove cluster from instrument panel. See INSTRUMENT CLUSTER R & I under REMOVAL & INSTALLATION. Using voltmeter, verify battery voltage at cluster connector C2, terminal No. 12 (Red/Yellow wire) and oil pressure gauge terminal. See Figure . Inspect cluster for damage. If battery voltage is present, go to next step. If voltage is not present, repair circuit No. 640 (Red/Yellow wire) and retest system.
With ignition switch in OFF position, check continuity of instrument cluster circuit No. 570 (Black/White wire) and gauge ground circuitry. If ground circuitry is okay, go to next step. If ground circuitry is faulty, repair wiring as necessary.
Turn ignition switch to ON position. If oil pressure gauge reads "L" or below, go to next step. If gauge reads higher than "L", go to step 7).
Disconnect oil pressure switch and short lead to engine ground. If gauge indicates about mid-scale or slightly above, replace oil pressure switch. If gauge does not read in mid-scale, go to next step.
With ignition switch in OFF position, using an ohmmeter, check sending unit/switch wiring and instrument cluster printed circuit for shorts or opens by physically flexing wiring and observing continuity. Continuity reading should not fluctuate. If wiring and printed circuit test okay, replace oil pressure gauge. See COOLANT TEMPERATURE/OIL PRESSURE GAUGE under REMOVAL & INSTALLATION. If wiring or printed circuit do not test okay, repair wiring or replace instrument cluster. See INSTRUMENT CLUSTER R & I under REMOVAL & INSTALLATION.