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 227 of 1207

TM 9-2320-361-20
Table 2-4. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
40. HOT WATER PERSONNEL HEATER DOES NOT OPERATE OR DOES NOT OPERATE IN LOW POSITION
Test 1. Check horn operation.
Push horn button.
a. If horn fails to operate, go to malfunction 38.
b. If horn is operational, voltage is present at input of heater circuit breaker. Go to test 2.
c. If heater high/low switch operates in high, but fails to operate in low, go to test 5.
Test 2. Check heater high/low switch for power input.
Step 1.
Step 2.
Step 3.
Step 4.
Set multimeter to a range that will measure 24 Vdc.
Disconnect lead 10 at rear of heater switch.
Touch multimeter positive lead to contact end of lead 10 at heater switch.
Touch multimeter negative lead 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. Test for power output at heater high/low switch,
Step 1. Set multimeter to range that will measure 24 Vdc.
Step 2. Disconnect lead 400 at rear of heater switch.
Step 3. Touch positive lead of multimeter to contact end of power output at the heater switch.
Step 4. Touch negative lead of multimeter to frame ground. Voltage should be present.
a. If voltage is present, go to test 4.
b. If voltage is not present, replace heater switch (para. 4-34).
Test 4. Test personnel heater for power input.
Step 1. Ensure heater switch is in high position.
Step 2. Set multimeter to a range that will measure 24 Vdc.
Step 3. Disconnect lead 400 from personnel heater.
Step 4. Touch multimeter positive lead to contact end of lead 400.
Step 5. Touch multimeter negative lead to frame ground. Voltage should be present.
a. If voltage is not present, replace or repair lead 400 (para. 4-51).
b. If voltage is present, and personnel heater fails to operate, replace personnel heater
(para. 11-42).
Test 5. Test blower motor resistor.
Step 1. Set multimeter to RX1.
Step 2. Ensure heater switch is set to low position.
Step 3. Touch positive lead of multimeter to one lead on resistor.
Step 4. Touch negative lead of multimeter to the other lead of resistor.
a. Multimeter should measure between 4.5 and 5.5 ohms.
b. If resistance is not within tolerance of 4.5 and 5.5 ohms, replace resistor (para. 4-35).
2-142


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