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 230 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Test 2. Check ether start system electrical source.

Operate personnel heater blower motor with switch in HIGH position (TM 9-2320-272-10).

a.

If personnel heater blower motor does not operate, perform malfunction 39.

b.

If personnel heater blower motor operates, go to test 3.

Test 3. Test lead 570 for voltage at ether valve.

Step 1.

Disconnect lead 570 at ether valve.

Step 2.

Set multimeter to 50-volt range. Connect positive lead to disconnected lead 570 and

multimeter negative lead to ground.

Step 3.

Turn battery switch to ON position.

Step 4.

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

a.

If meter indicates battery voltage and ether valve does not function, replace ether

valve (para. 3-35).

b.

If no voltage is indicated, go to test 4.

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