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 255 of 1015

TM 9-2320-272-24-1

Table 2-3. Electrical Troubleshooting (Contd).

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

38. HEATER WILL NOT OPERATE WITH SWITCH IN HIGH POSITION (LOW POSITION OPERATION NORMAL)

Step 1.

Place battery to OFF position.

Step 2.

Disconnect lead 5C from heater switch.

Step 3.

Place battery switch to ON position.

Step 4.

Set multimeter to 50-volt range.

Step 5.

Connect multimeter negative lead to vehicle chassis ground and positive lead to

lead 5C. Multimeter should indicate 12-13 volts.

a. If battery voltage is not indicated, perform malfunction 27, test 1.

b.

If battery voltage is indicated, replace defective heater switch (para. 3-107).

END OF TESTING!

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