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 203 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Test 7. Test continuity of protective control box harness.

Step 1.

Set parking brake (TM 9-2320-272-10).

Step 2.

Place transmission in neutral.

Step 3.

Disconnect lead 498 at neutral start switch.

Step 4.

Connect multimeter positive lead to contact end of lead 498 and negative lead to contact

end of lead 498 at neutral start switch.

a.

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

lead 498 (para. 3-131).

b.

If continuity is indicated, connect lead 498 to start switch (pin S) and go to step 5.

Step 5.

Disconnect lead 499 at neutral start switch.

Step 6.

Connect multimeter positive lead to neutral start switch contact end of lead 499 and

negative lead to neutral start contact end of lead 498.

a.

Multimeter should indicate continuity. If continuity is not indicated, replace neutral

start switch (para. 3-98).

b.

If continuity is indicated, connect lead 498 to neutral start switch and go to

step 7.

2-115