TM 9-2320-260-20
Table 2-4. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
Test 5. Test continuity of fuel level sending unit.
Step 1. Set multimeter to RX1 scale.
Step 2. Connect multimeter leads to fuel level sending unit.
Step 3. Position float in empty position.
a. If resistance is between 0.00 and 0.50 ohms, go to step 4.
b. Replace fuel level sending unit if resistance is not between 0.00 and 0.50 ohms
Step 4. Set multimeter to RX10 scale.
Step 5. Position float in full position.
a. If resistance is between 29.50 and 31.50, reinstall fuel level sending unit (para. 4-24)
and recheck gage operation.
b. Replace fuel level sending unit if resistance is not between 29.50 and 31.50
Test 6. Test fuel gage switch operation (M817 and M818 only).
Step 1. Disconnect lead 28 from fuel gage switch output pin A.
Step 2. Disconnect leads 28 and 29 inputs from pins B and D.
Step 3. Position fuel gage switch to "L."
Step 4. Set multimeter to RX1 scale.
Step 5. Touch positive lead of multimeter to pin B.
Step 6. Touch negative lead of multimeter to pin A. Continuity should be present.
a. If continuity is present, go to step 7.
b. Replace fuel selector switch if continuity is not present (para. 4-18).
Step 7. Position fuel gage switch to "R."
Step 8. Touch positive lead of multimeter to pin D.
Step 9. Touch negative lead of multimeter to pin A. Continuity should be present.
a. If continuity is present, go to test 7.
b. Replace fuel selector switch if continuity is not present (para. 4-18).
Test 7. Test continuity of lead 28 (M817 and M818 only).
Step 1. Disconnect lead 28 from fuel gage switch output pin A.
Step 2. Disconnect lead 28 from fuel gage.
Step 3. Set multimeter to RX1 scale.
Step 4. Touch multimeter positive lead to contact end of lead 28 at fuel gage switch.
Step 5. Touch multimeter negative lead to contact end of lead 28 at fuel gage.
a. Continuity should be present.
b. Repair or replace lead 28 if continuity is not present (para. 4-52).
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