ELECTRICAL TROUBLESHOOTING - continued - TM-9-2320-386-24-1-10093

TM 9-2320-386-24-1-1

0012 00

Electrical Troubleshooting (Contd)

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

NOTE

Access cover was removed in test 3.

A decrease in input voltage normally causes an increase in

alternator output voltage.

Step

Start engine (TM 9-2320-386-10).

Step

Set engine speed at 1200 rpm.

Step

Turn headlights and accessories to ON position.

Step

Using multimeter, measure alternator output voltage at positive terminal (lead 2).

a. If output voltage is between 24.0 and 26.0 Vdc, replace alternator (Prestolite)

(WP 0089 00) or (Leece-Neville) (WP 0090 00).

b. If output voltage is more than 28.5 Vdc, go to test 5 and check voltage drop on lead 2.

Test 5. Test voltage drop on lead 2.

Step 1. Place multimeter positive lead on alternator positive output. Place multimeter negative

lead on starter solenoid lug at leads 2, 6, and 14.

Step 2. If voltage drop on lead 2 is greater than 0.4 volts, replace or repair lead

(WP 0125 00) and go to test 2 and retest.

Step 3. If voltage drop on lead 2 is less than 0.4 volts (normal), voltage regulator output is too

high. Replace alternator (Prestolite) (WP 0089 00) or (Leece-Neville) (WP 0090 00).

Test 6. Test battery voltage into accessory/battery switch (malfunction 2, test 5).

Step 1. Disconnect lead 1 from accessory/battery switch.

Step 2. Turn accessory/battery switch to ON position.

Step 3. Check voltage at accessory/battery switch. Battery voltage should be present.

a. If battery voltage is present, go to step 4 and check continuity of lead 1.

b. If voltage is not present, perform malfunction 2, test 5, step 4 to test continuity of

accessory/battery switch.

c. If continuity is found in accessory/battery switch, go to step 4.

Step 4. With both ends of lead 1 disconnected, check continuity.

a. If continuity is found, reconnect lead 1 to accessory/battery switch. With

accessory/battery switch in ON position, battery voltage should be present at lead 1.

b. If continuity is not present, replace or repair lead 1 (WP 0125 00).

END OF TESTING!

6. BATTERIES NOT CHARGING PROPERLY (BATTERY GAUGE IN YELLOW OR RIGHT-HAND RED)

NOTE

If STE/ICE-R is available, perform NG50 Charging Circuit Tests

(WP 0017 00).

Test 1. Check for loose or missing fan drivebelt.

Adjust or replace fan drivebelt (WP 0084 00).

Test 2. Test battery voltage (malfunction 5, test 2).

0012 00-10