Table 2-4. Electrical Troubleshooting (Contd).
MALFUNCTION
TEST OR INSPECTION
CORRECTIVE ACTION
31. FUEL GAGE INOPERATIVE
WARNING
Do not perform testing near fuel tank with fill cap or sending
unit removed. Fuel may ignite, causing injury to personnel.
NOTE
Ensure fuel tank is not empty before proceeding to test 1.
If STE/ICE is available, perform NG31 - gage test (chapter 2,
section VII).
Testing for left and right fuel level sending units are
performed the same way, except lead 29 is for the right fuel
tank and lead 28 is for the left fuel tank. The following test
is for the left fuel tank.
On M817 and M818 models only, make sure fuel gage switch
is positioned to the fuel tank being tested.
On M818 models. remove the deck date above the fuel tank
for access to sending unit.
Test 1. Test for battery voltage to fuel level sending unit.
Step 1. Turn battery switch to ON position.
Step 2. Turn ignition switch to RUN position.
Step 3. Disconnect lead 28 from fuel level sending unit.
Step 4. Set multimeter to a voltage range that will measure 24 volts.
Step 5. Touch negative lead of multimeter to frame ground.
Step 6. Touch positive lead of multimeter to contact end of lead 28.
a. If battery voltage is present, go to test 2.
b. If battery voltage is not present, go to test 3.
Test 2. Test fuel gage operation.
Step 1. Turn battery switch and ignition switch to OFF position.
Step 2. With lead 28 already disconnected from sending unit, touch contact end to frame ground.
Step 3. Turn battery switch to ON position.
Step 4. Turn ignition switch to ON position.
Step 5. Fuel gage should read "EMPTY."
a. If fuel gage shows "EMPTY," go to step 6.
b. Replace fuel gage if fuel gage does not show "EMPTY" (para. 4-10).
Step 6. Lift lead 28 from frame ground. Fuel gage should now read "FULL."
a. If fuel gage shows "FULL," it is operational. Remove fuel level sending unit
b. Replace fuel gage if fuel gage does not show "FULL" (para. 4-10).
Test 3. Test fuel gage voltage.
Go to malfunction 29, test 2 and check battery voltage into fuel gage.
Test 4. Test continuity of lead 28.
Step 1. Turn ignition switch and battery switch to OFF position.
Step 2. Disconnect lead 28 from fuel level sending unit.
Step 3. Disconnect lead 28 at fuel gage.
Step 4. Connect jumper wire from contact end of lead 28 at fuel level sending unit to frame
ground.
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