TM-9-2320-361-20

2-1/2-TON, 6x6, M44A2 SERIES TRUCKS (MULTIFUEL)

TECHNICAL MANUAL; UNIT MAINTENANCE

OCTOBER 1991
TM-9-2320-361-20

  TM-9-2320-361-20 - Page 229 of 1207

TM 9-2320-361-20
MALFUNCTION
TEST OR lNSPECTION
CORRECTIVE ACTION
Table 2-4. Electrical Troubleshooting (Contd).
41. PERSONNEL FUEL BURNING HEATER INOPERATIVE
Test 1. Check horn operation.
Push horn button.
a. If horn is operational, voltage is present at input of personnel heater circuit breaker,
go to test 2.
b. If horn fails to operate, go to malfunction 38.
Test 2. Test lead 10 for power input to heater control box.
Step 1.
Step 2.
Step 3.
Step 4.
Set multimeter to a range that will measure 24 Vdc.
Disconnect lead 10 from heater control box.
Touch multimeter positive lead to contact end of lead 10.
Touch negative lead of multimeter to frame ground. Voltage should be present.
a. If voltage is present, go to test 3.
b. If voltage is not present, replace or repair lead 10 (para. 4-51).
Test 3. Check heater control box for power output.
Step 1. Set multimeter to a range that will measure 24 Vdc.
Step 2. Disconnect harness connector from rear of control box.
Step 3. Set heater control switch to start and hold.
Step 4. Set heater control heat switch to high.
Step 5. Touch positive lead of multimeter to pin A
Step 6. Touch negative lead of multimeter to frame ground.
Step 7. Repeat steps 4 and 5 for pins B, C, and D. Voltage should be present.
a. If voltage is present at all pins tested, go to test 4.
b. If voltage is not present at one or more pins, replace heater control box (para. 14-3).
Test 4. Check for input power at fuel pump.
Step 1. Set multimeter to a range that will measure 24 Vdc.
Step 2. Disconnect lead 25 at fuel pump.
Step 3. Touch multimeter positive lead to contact end of lead 25.
Step 4. Touch multimeter negative lead to frame ground. Voltage should be present.
a. If voltage is present, replace personnel fuel burning heater (para. 14-2).
b. If voltage is not present, replace or repair lead 25 (para. 4-51).
Test 5. Check fuel pump for proper operation.
Refer to mechanical troubleshooting table 2-2, malfunction 82.
Test 6. Check for power input at personnel heater.
Step 1. Set multimeter to a voltage that will measure 24 Vdc.
Step 2. Disconnect harness connector at personnel heater.
Step 3. Set heater control switch to run.
Step 4. Touch multimeter positive lead to pin A of harness connector.
Step 5. Touch multimeter negative lead to frame ground.
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