
TROUBLESHOOTING AND ELECTRICAL SYSTEM
Test Procedures
2005 FE350 Gasoline Vehicle Maintenance and Service Supplement
Page 11-39
11
5. If the readings are within the specifications listed above, the fuel level sending unit is working properly.
If the readings are incorrect, the fuel level sending unit has failed and the fuel tank must be replaced.
See
Fuel Tank Removal, Section 14, Page 14-23.
6. If the readings are correct and the fuel gauge does not function correctly, check the continuity of the
orange wire from the fuel level sending unit to the fuel gauge/hour meter. Leave the battery disconnected
while checking continuity. Also check the continuity of the blue wire from the fuel gauge/hour meter to the
key switch, and the black ground wires at the fuel level sending unit and at the fuel gauge/hour meter.
See Fuel Gauge/Hour Meter Removal, Section 12, Page 12-23.
7. If the readings are correct according to the position of the float, but give an incorrect reading on the fuel
gauge/hour meter, test the fuel gauge/hour meter.
See Test Procedure 27 – Fuel Gauge on
page 11-39.
TEST PROCEDURE 27 – FUEL GAUGE
See General Warning, Section 10, Page 10-1.
1. Disconnect the battery cables as instructed.
See WARNING “To avoid unintentionally starting...” in
General Warning, Section 10, Page 10-1.
2. Remove the center dash assembly to gain access to the back of the fuel gauge/hour meter.
See Key
Switch Removal, Section 12, Page 12-13.
3. Disconnect the orange wire from the fuel gauge/hour meter.
4. Set a multimeter to 20 volts DC and place the red (+) probe of the multimeter on the positive (+) post of
the battery. Place the black (–) probe on the negative (–) post of the battery. Record the voltage reading.
5. Set a multimeter to 20 volts DC and place the red (+) probe of the multimeter on the (2) terminal of the
fuel gauge/hour meter with the blue wire. Place the black (–) probe on the (3) terminal of the fuel gauge/
hour meter with the black wire
(Figure 11-40, Page 11-39)
.
6. Connect battery cables, positive (+) cable first, and tighten hardware to 12 ft-lb (16 N·m).
7. Turn the key switch ON. The voltage reading should be the same as the battery voltage reading recorded
earlier. If not, check the continuity of the blue and black wires
(Figure 11-40, Page 11-39)
.
8. The orange wire should remain disconnected for this step. With the black probe still on the terminal (3)
of the fuel gauge/hour meter, place the red (+) probe of the multimeter on the (1) terminal of the fuel
gauge/hour meter. The voltage reading should be the same as the full battery voltage reading obtained
in step 4. If the reading is incorrect, replace fuel gauge/hour meter
(Figure 11-41, Page 11-39)
.
Figure 11-40 Fuel Gauge Test
Figure 11-41 Fuel Gauge Voltage Test
2m
20
m
200
m
2k
200
200
200
200
20
2
200
m
500
20k
200k
2000
k
1000
OFF
WAVETEK
5XL
V
V
V
A
!
!
COM
200nA
MAX
1000 ---
750V
FUSED
1
3
2
18-GAUGE
BLUE WIRE
TO NO. 1 ON
KEY SWITCH
18-GAUGE BLACK
WIRE TO GROUND
Remove 18-gauge
orange wire to
sending unit.
18-GAUGE WHITE
WIRE TO SOLENOID
20 VDC
SETTING
2m
20
m
200
m
2k
200
200
200
200
20
2
200
m
500
20k
200k
2000
k
1000
OFF
WAVETEK
5XL
V
V
V
A
!
!
COM
200nA
MAX
1000 ---
750V
FUSED
1
3
2
18-GAUGE
ORANGE
WIRE
20 VDC
SETTING