Charging System: Testing and Inspection

Two different alternators are used, one manufactured by Bosch and the other by Motorola. However, the test procedures for both alternators are identical.

1. Connect a suitable volt/amp tester, load pile, and battery cut-out switch to charging system following manufacturer's instructions.
2. Start and operate engine until normal operating temperature is obtained, then maintain engine speed at 3000 RPM. Ensure all electrical accessories are switched off before testing system.
3. Adjust load pile to approximately 20 amps. Do not allow voltage to drop below 12 volts.
4. Turn battery cutout switch to the OFF position.
5. Adjust load resistance until ammeter reads 45 amps for a 65 amp alternator and 60 amps for a 90 amp alternator.
6. Check that voltmeter reads between 12.5 and 14.5 volts.
7. If reading is still not within specification, repair or replace alternator. Before replacing alternator, ensure charging system wiring harness is properly routed, free from breaks or frayed insulation, and that connectors are free of corrosion.