TM 5-4520-253-13
Table 3-3. Unit Maintenance Troubleshooting – Continued
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Step 3. Check fuel filter.
Clean and inspect
described in table
fuel filter as
3-2.
Step 4. Check fuel pump operation by checking for 24 V dc between fuel pump con-
nector and case.
If 24 V dc is present, replace fuel pump.
Step 5. Check fuel pump cable.
Disconnect cable from heater. Check fuel pump plug
for loose connections or damage.
Check cable wires for continuity:
Replace defective cable.
To remove and install plug, refer to REMOVE/
INSTALL POWER, FUEL PUMP, AND ROOM THERMOSTAT PLUGS,
page 3-124.
Step 6. Check external fuel pump receptacle for damage. Inspect for burned contacts
and other damage.
Replace defective receptacle as described in lNSPECT/REMOVE/lNSTALL
POWER RECEPTACLE AND EXTERNAL FUEL PUMP RECEPTACLE,
page 3-60.
Step 7. Check
Death or serious injury could occur if pre-
cautions are not taken when maintaining this
equipment. Be sure that any power cables
are unplugged/disconnected. Be sure that the
equipment is properly grounded. Always
have another person standing by who is
trained in electric shock first aid.
external fuel pump receptacle for 24 V dc.
If current is not present, forward heater to intermediate maintenance for
testing of PC board.
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