TM-9-2320-272-24-1

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; UNIT, DIRECT SUPPORT, AND GENERAL SUPPORT MAINTENANCE MANUAL; VOLUME 1 OF 4

JUNE 1998

TM-9-2320-272-24-1 - Page 205 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Test 8. Test continuity of protective control box harness.

NOTE

Sealant must be removed before removing leads.

Step 1.

Disconnect lead 566 at alternator.

a.

Remove two screws (2), lockwashers (3), and terminal cover (1) from alternator (4).

b.

Remove nut (7), washer (6), lockwasher (5), and lead 566 from alternator (4).

Step 2.

Connect multimeter positive lead to pin F at harness connector and negative lead to

contact end of lead 566 at alternator.

a.

Multimeter should indicate continuity. If continuity is not indicated, repair broken

lead 566 (para. 3-131).

b.

If continuity is indicated, connect harness connector to protective control box. DO

NOT connect lead 566 to alternator. Go to test 9.

Test 9. Test starter lockout signal.

Attempt to start engine with lead 566 disconnected from alternator.

a.

If engine fails to start, replace protective control box (para. 3-115).

b. If engine starts, replace alternator (para. 3-79 or 3-80).

END OF TESTING!

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