TM-9-2320-361-24-1

2-1/2 TON, 6X6, M44A2 SERIES TRUCKS

TECHNICAL MANUAL; FIELD AND SUSTAINMENT MAINTENANCE PART 1 OF 2

AUGUST 2006

TM-9-2320-361-24-1 - Page 122 of 1176

TM 9-2320-361-24-1

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MECHANICAL SYSTEMS TROUBLESHOOTING - UNIT (Contd)

Table 21. Personnel Fuel Burning Heater Troubleshooting Procedures.

MALFUNCTION

TEST OR INSPECTION

CORRECTIVE ACTION

1. HEATER WILL NOT

OPERATE IN HIGH OR

LOW SWITCH POSITION

Test 1. Check horn operation.

Push horn button.

Test 2. Test lead 10 for power input

to heater control box.

1. Set multimeter to range

that will measure 24 VDC.

2. Disconnect lead 10 from

heater control box.

3. Touch multimeter positive

lead to contact end of

lead 10.

4. Touch negative lead of

multimeter to frame

ground. Voltage should be

present.

Test 3. Check heater control box for

power output.

1. Set multimeter to range

that will measure 24 VDC.

2. Disconnect harness

connector from rear of

control box.

3. Set heater control switch to

START and hold.

4. Set heater control heat

switch to HIGH.

5. Touch positive lead of

multimeter to pin A.

6. Touch negative lead of

multimeter to frame

ground.

7. Repeat steps 5 and 6 for

pins B, C, and D. Voltage

should be present.

1. If horn is operational, voltage is

present at input of personnel

heater circuit breaker. Go to

test 2.

2. If horn fails to operate, go to

WP 0014 00, table 1,

malfunction 10.

1. If voltage is present, go to test 3.

2. If voltage is not present, repair or

replace lead 10 (WP 0090 00).

1. If voltage is present at all pins

tested, go to test 4.

2. If voltage is not present at one or

more pins, replace heater control

box (WP 0352 00).