Charging System: Testing and Inspection

1. Connect a suitable volt/amp tester to electrical system following manufacturers' instructions. Alternator output voltage should be checked between the battery positive post and the alternator ground.
2. Connect a suitable tachometer to engine, start engine and run until it reaches normal operating temperature.
3. Apply current load to alternator and set engine to run at following speeds. Engine RPM specifications are approximate speeds calculated to obtain the alternator RPM specified for testing.
a. 55 amp alternator, 900 RPM.
b. 65 amp alternator, 950 RPM.
c. 70 amp Motorola, 800 RPM.
d. 70 amp Bosch, 850 RPM.
f. 80 amp alternator, 800 RPM.
4. Alternator should deliver specified output, at the rated voltage, as listed in ``Alternator Specifications.''
5. If output is not within specifications, check drive belt, feed and ground circuits, and repair as needed.
6. If wiring and drive belt are satisfactory, but output is not within specifications, alternator must be repaired or replaced.