TM 9-2320-363-20-1
Table 3-1. Troubleshooting (Cont)
Malfunction
Test or inspection
Corrective action
ELECTRICAL SYSTEM (CONT)
Auxiliary Heater Circuits (Cont)
Step 6.
Disconnect lead 422B from restriction thermostat. Check for +24 VDC at
lead 422B with auxiliary heater on/off switch closed and auxiliary heater
high/low switch in high mode.
If no voltage is present, repair auxiliary heater (notify direct
support maintenance).
Step 7.
Disconnect lead 422B at line disconnect. Check for +24 VDC at lead 422B.
If +24 VDC is present, go to step 8. If no voltage is present,
repair lead 422B (page 3-2).
Step 8.
Disconnect lead 422B at disconnect to heater. Check for +24 VDC at
lead 422B.
If +24 VDC is present, replace heater. If no voltage is present,
repair lead 422B (page 3-2).
4. AUXILIARY HEATER FUEL PUMP DOES NOT OPERATE, REMAINING AUXILIARY HEATER
CIRCUITS OPERATING.
Step 1.
Disconnect lead 58E from auxiliary heater fuel pump. Check for +12 VDC at
lead 58E with auxiliary heater on/off switch closed.
If +12 VDC is present, go to step 2. If no voltage is present,
repair lead 58E (page 3-2).
Step 2.
Disconnect auxiliary heater fuel pump ground lead from ground. Check
continuity between ground lead and ground.
If continuity is indicated, replace auxiliary heater fuel pump
(page 4-816). If no continuity is indicated, repair ground lead
(page 3-2).
5. AUXILIARY HEATER WATER PUMP DOES NOT OPERATE, REMAINING AUXILIARY CIRCUITS
OPERATING.
Step 1.
Disconnect lead 58E from auxiliary heater fuel pump. Check for +12 VDC at
lead 58E with auxiliary heater on/off switch closed.
If +12 VDC is present, go to step 2. If no voltage is present,
repair lead 58E (page 3-2).
Step 2.
Check for continuity between auxiliary heater fuel pump ground lead and
ground.
If continuity is indicated, replace auxiliary heater fuel pump
(page 4-816). If no continuity is Indicated, repair ground lead
(page 3-2).
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