TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004

CHANGE 2

TM-9-2320-272-10 - Page 364 of 481

TM 9-2320-272-10

3-15

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

Table 3-1. Troubleshooting (Contd).

39. CEILING LIGHTS AND SERVICE RECEPTACLES FAIL TO ENERGIZE WHEN

DOORS ARE CLOSED UNDER BLACKOUT CONDITIONS (110 VOLT SYSTEM).

Step 1. Check to see if blackout circuit switch and/or main circuit breaker

switches are turned off (para. 2-27).

If off, turn on switches.

Step 2. Check to see if blackout switch is turned off.

If off, turn on blackout switch.

Step 3. Check outside power cable for secure connections if electrical power

is supplied from outside source.

If not, connect power cable securely to power entrance receptacle

and power source.

40. EMERGENCY LIGHT, BLACKOUT LIGHT, AND CEILING LIGHTS FAIL TO

ILLUMINATE (24 VOLT SYSTEM).

Step 1. Check to see if main circuit breaker and/or light switches are turned off.

If not, turn on main circuit breaker or light switches.

Step 2. Check outside power cable for secure connections if electrical power

is supplied from outside source.

If not, connect power cable securely to power entrance receptacle

and power source.

41. HEATER WILL NOT IGNITE.

Step 1. Check to see if main circuit breaker and/or heater switches are

turned off (para. 2-27).

If off, turn on main circuit breaker or heater switches.

Step 2. Check to see if thermostat is set to desired temperature.

If not, set thermostat properly.

Step 3. Check fuel level on fuel gauge.

Fill fuel tank(s) as necessary.