Test B: Voltmeter Inaccurate

NOTE: Ensure charging system is operating properly before proceeding with this test. See appropriate GENERATORS & REGULATORS article in STARTING & CHARGING SYSTEMS.

Turn ignition switch to RUN position. Observe voltmeter. If voltmeter registers in normal range, go to step 4. If voltmeter registers higher than normal range, replace instrument cluster. If voltmeter registers lower than normal range, go to next step.

NOTE: Power feed to voltmeter is from fuse No. 4 (10-amp) in battery junction box. Wire changes colors at splice S175 (located at left rear of engine compartment on firewall) from Yellow to Red/White where harness enters passenger compartment.

Inspect fuse No. 4 (10-amp) in battery junction box. If fuse is okay, go to next step. If fuse is blown, install new fuse and retest. If fuse blows again, repair circuit for short to ground in Yellow wire to fuse No. 4. See POWER DISTRIBUTION article in WIRING DIAGRAMS.
Remove instrument cluster. Disconnect instrument cluster harness connector C224. See Figure. Measure voltage between ground and terminal No. 3 (Red/white wire) at instrument cluster harness connector C224. If battery voltage exists, replace instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Retest system. If battery voltage is not present, repair open or short in Yellow wire between fuse No. 4 (10-amp) and instrument cluster harness connector C224.
Start engine. If gauge is in normal range, system is okay. If gauge is not in normal range, check for poor connection at bulkhead connector and instrument cluster ground G203 (located at upper left side of instrument panel). See WIRING DIAGRAMS . Repair as necessary. Retest system.