TM 1-1740-221-13&P&P
FIELD MAINTENANCE
ALTERNATOR
INITIAL SETUP:
Test Equipment
References
Multimeter (WP 0157, Item 14)
Tools and Special Tools
General Mechanic Tool Box (WP 0157, Item 24)
Personnel Required
91B, Light Wheel Vehicle Mechanic
INSPECTION
1. Inspect alternator wiring for corrosion, loose connections and breaks in insulation.
2. Inspect for proper mounting and for any damage affecting serviceability.
3. Verify engine/alternator belt tension is correct (WP 0041).
END OF TASK
TEST
WARNING
Remove all jewelry such as rings, ID tags, watches, and bracelets. If jewelry or tools contact a
battery positive terminal, a direct short will result in instant heating or electric shock, damage to
equipment, and injury to personnel.
ALTERNATOR TEST
1. Ignition switch on.
2. Check for 12 volts at red wire, #1 (Figure 1, Item 2).
3. Disconnect electrical connector (Figure 1, Item 3).
4. Check for 12 volts at orange wire, #3 (Figure 1, Item 3).
5. Voltage reading of 12 volts.
6. Start engine, measure voltage at output terminal (Figure 1, Item 2).
7. Voltage reading should now be between 13.8 and 14.8 volts nominally.
8. Shut down engine.
9. Replace alternator if readings are low (no alternator output) or too high (overcharging batteries).
END OF TASK
00351