TM 9-2320-361-20 Table 2-4. Electrical Troubleshooting (Contd). MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION Test 2. Test charging system output voltage. Step 1. Open door of battery compartment. Loosen two thumbscrews and slide batteries onto running board. Step 2. Use multimeter to check battery voltage. NOTE If vehicle is equipped with a slave receptacle, check voltage at receptacle. Step 3. Start engine (TM 9-2320-361-10). Step 4. Set engine speed at 1200 rpm. Step 5. Turn vehicle headlights and accessories to ON position. Step 6. Use multimeter to check battery voltage. Charging voltage on batteries should be 28.0 ± 0.2 Vdc. a. b. c. d. e. f. If battery voltage measures 24.0 Vdc, alternator has no output. Go to test 3 and check input voltage. If battery voltage is between 24.0 and 26.0 Vdc, alternator output is weak. Go to test 3 and check input voltage. If battery voltage measures 28.0 ± 0.2 Vdc and battery generator on instrument panel shows no voltage, an electrical problem exists between generator and accessory/ignition switch. Go to malfunction 2, test 4, step 3. If battery voltage measures between 26.0 and 30.0 Vdc, adjust voltage regulator (para. 4-3) in alternator until voltage across batteries is 28.0 ± 0.2 Vdc. Go to step 7 and check regulator stability. If regulator voltage across batteries cannot be adjusted to 28.0 ± 0.2 Vdc, replace alternator (para. 4-3). 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 (para. 4-3). Step 7. Check voltage regulator stability as follows: a. b. c. d. e. f. g. Decrease engine speed to 1000 rpm with headlights in ON position. Regulated battery voltage should remain at 28.0 ± 0.2 Vdc. If battery voltage drops below 27.5 Vdc, replace alternator (para. 4-3). Increase engine speed to 2000 rpm. Regulated battery voltage should remain at 28.0 ± 0.2 Vdc. If battery voltage increases above 28.5 Vdc, replace alternator (para. 4-3). Return engine speed to 1200 rpm. Turn headlights OFF and ON and observe change of battery voltage. If battery voltage changes more than ± 0.5 Vdc and does not return quickly to 28.0 ± 0.2 Vdc, replace alternator (para. 4-3). 2-90