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 248 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Step 8.

Connect lead 578 to air pressure switch A.

Step 9.

Disconnect wiring harness at failsafe warning control module.

Step 10. Touch positive lead of multimeter to pin F (lead 578) and negative lead of multimeter to

frame ground.

a.

If continuity is present, go to step 11.

b.

If continuity is not present, replace lead 578 (para. 3-131).

Step 11. Touch positive lead of multimeter to pin H (lead 57) and negative lead of multimeter to

frame ground.

a. If continuity is present, go to step 12.

b. If continuity is not present, replace lead 57 (para. 3-131).

Step 12. Touch positive lead of multimeter to pin D (lead 350) and negative lead of multimeter to

frame ground.

a. If continuity is present, go to step 13.

b.

If continuity is not present, replace lead 350. (Refer to Digest Article, Engine

Overheating Warning System.)

Step 13. Ensure parking brake is engaged (TM 9-2320-272-10).

Step 14. Touch positive lead of multimeter to pin I (lead 584) and negative lead of multimeter to

frame ground.

If low air warning buzzer will not shut off, replace.

a.

If continuity is not present, replace lead 584 (para. 3-131).

END OF TESTING!

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