TM-9-2320-361-24-1 Field Maintenance Manual Volume 1 for M44A2 Series Trucks
Page 204 of 1176
MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 1. NO ALTERNATOR OUTPUT 6. Check voltage regulator stability. Test 3. Test input voltage to alternator. 1. Turn headlights to OFF position. Stop engine. 2. Disconnect lead 1 from lead 568 at alternator. 3. Turn power accessory switch to ON position. 4. Check for battery voltage at contact end of lead 1. Voltage should be 24.0 VDC. 5. If alternator voltage across batteries cannot be adjusted to 28.0 ± 0.2 VDC, replace alternator (WP 0085 00). 6. If battery voltage is greater than 30.0 VDC, first try to adjust voltage regulator in alternator down to 28.0 VDC. If voltage regulator voltage cannot be adjusted to 28.0 VDC, replace alternator (WP 0085 00). 1. Decrease engine speed to 1000 RPM with headlights in ON position. Regulated battery voltage should remain at 28.0 ± 0.2 VDC. 2. If battery voltage drops below 27.5 VDC, replace alternator (WP 0085 00). 3. Increase engine speed to 2000 RPM. Regulated battery voltage should remain at 28.0 ± 0.2 VDC. 4. If battery voltage increases above 28.5 VDC, replace alternator (WP 0085 00). 5. Return engine speed to 1200 RPM. 6. Turn headlights on and off and observe change in battery voltage. 7. If battery voltage changes more than ± 0.5 VDC and does not return quickly to 28.0 ± 0.2 VDC, replace alternator (WP 0085 00). 1. If voltage is not present, open lead or bad connection exists in input circuit. Go to test 6. 2. If voltage is 24.0 VDC (normal), remove access cover on top of alternator to expose output terminal. 3. Reconnect lead 1 to lead 568. Go to test step 5. TM 9-2320-361-24-1 0012 00 0012 00-20 BATTERY AND CHARGING SYSTEM TROUBLESHOOTING (Contd) Table 3. Charging System (60 Amp) Troubleshooting Procedure (Contd).