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 231 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Test 4. Test lead 570 for voltage at ether start pressure switch.

Step 1.

Disconnect lead 570 to ether valve from ether start pressure switch.

Step 2.

Connect positive lead to lead 570 terminal on ether start pressure switch and negative

lead to chassis ground.

Step 3.

Crank engine, depress ether start switch, and observe multimeter.

a.

If meter indicates battery voltage, repair lead 570 to ether valve (para. 3-131).

b.

If no voltage is indicated, go to step 4.

Step 4.

Disconnect lead 570 at ether start switch.

Step 5.

Connect multimeter positive lead to lead 570 from ether start switch and negative lead

to chassis ground.

Step 6.

Crank engine, depress ether start switch, and observe multimeter.

a.

If multimeter indicates battery voltage, replace ether start pressure switch

(para. 3-33).

b.

If no voltage is indicated, go to test 5.

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