TM-9-2320-361-24-1 Field Maintenance Manual Volume 1 for M44A2 Series Trucks
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TM 9-2320-361-24-1 0015 00 0015 00-7 HEATING SYSTEMS TROUBLESHOOTING (Contd) MALFUNCTION TEST OR INSPECTION CORRECTIVE ACTION 2. HOT WATER PERSONNEL HEATER DOES NOT OPERATE OR DOES NOT OPERATE IN LOW POSITION Test 1. Check horn operation. Place power accessory switch to the ON position. Push horn button. Test 2. Check heater high/low switch for power input. 1. Set multimeter to a range that will measure 24 VDC. 2. Disconnect lead 10 at rear of heater switch. 3. Touch multimeter positive lead to contact end of lead 10 at heater switch. 4. Touch multimeter negative lead to frame ground. Voltage should be present. Test 3. Test for power output at heater high/low switch. 1. Set multimeter to a range that will measure 24 VDC. 2. Reconnect lead 10 and disconnect lead 400 at rear of heater switch at the high switch side. Place switch in the high position. 3. Touch positive lead of multimeter to contact end of power output at the heater switch. 4. Touch multimeter negative lead to frame ground. Voltage should be present. 1. If horn fails to operate, go to WP 0014 00, table 1, malfunction 10. 2. If horn is operational, voltage is present at input of heater circuit breaker. Go to test 2. 3. If heater high/low switch operates in high but fails to operate in low, go to test 5. 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, go to test 4. 2. If voltage is not present, replace heater switch (WP 0116 00). Table 1. Heating Systems Troubleshooting Procedures (Contd). TEST 2 STEPS 3 AND 4 TEST 3 STEPS 3 AND 4 HEATER SWITCH LEAD 400