Service manual

8−10
62-11389
18
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13
1. Fuel Level Sensor
2. Gasket
3. Focus Tube
4. Sensor Flange
5. Fuel Level Sensor Flange
6. Fuel Tank
7. Wire 1MP26 - FLSC (Connection C)
8. Wire SP6 - FLSB (Connection B)
9. Wire SP5 - FLSA (Connection A)
10. Fuse (FLS = 3A)
11. White Wire (Connection C)
12. Black Wire (Connection B)
13. Red Wire (Connection A)
14. Ground (Shield)
15. Yellow Wire (Connection C)
16. Black Wire (Connection B)
17. Red Wire (Connection A)
18. Wires From Sensor
Figure 8−9 Fuel Level Sensor
d. Energize sensor circuit, refer to Note 2, page 7−2.
Check power (approximately 12 VDC) from SP5 (9,
Figure 8−9) through to connector (13). Check ground
from SP6 (8) through connector (12). Check signal
(greater than 0.24 VDC and less than 5VDC) at mi-
croprocessor (1MP-26).
e. If checks in the preceding step are OK, remove the
fuel level sensor, focus tube and gaskets. With the
trailer level, verify that the fuel level sensor flange is
within one-half bubble of level using a 24 inch level.
Adjust tank mounting as required.
CAUTION
Torque fuel level sensor mounting screws
to 15 to 18 inch/pounds. DO NOT over tight-
en, as little as 20 inch/pounds will damage
the sensor.
f. Using new gaskets, reinstall fuel level sensor com-
ponents. The mounting holes are not symmetrical,
there is an alignment hole in the sensor, alignment
holes and index dimples in the gaskets and an align-
ment notch in the focus tube flange to assist in align-
ing the components. Install mounting screws and
washers in all mounting holes and bring to finger tight.
Tighten in accordance with the instructions provided
in the preceding CAUTION
g. With the fuel tank empty the output reading should be
approximately 0.25 VDC.
h. With the fuel tank full, the output reading should be
approximately 4.75 VDC.
i. Start unit and check for leaks.
8.5.7 Fuel Heater
The optional fuel heater (item 6, Figure 8−5) applies
heat to fuel in the fuel filter. Heating the fuel dissolves /
prevents paraffin wax crystals (and ice) that form when
diesel fuel is chilled thus enabling the water separator to
work more efficiently and to prevent the filter from
plugging with wax and/or ice crystals. When the ambient
air sensor is reading 77_F (25_C) or higher, the
microprocessor will not enable this circuit. Also, the
heater is fitted with an internal temperature switch
(FHTS - see schematic diagrams, Section 10) which will
close, on a temperature fall, to energize the heater
element at temperatures below 45_F (7.2_C) and open,
on a temperature rise, to de-energize the heater
element at 75_F (23.9_C).
To test the fuel heater, do the following:
a. Using Unit Data (refer to Section 3.13), check to en-
sure the Ambient Air Temperature reading is below
77_F (25_C), if the reading is below this temperature
the fuel heater relay (FHR) should be energized. If the
relay does not energize, check for power from micro-
processor terminal 4MP16 to the relay coil and
ground from the coil connector.
b. Check for power from SP50, through fuse F19, the re-
lay contacts and HC16 to the fuel heater connector.
Check also for ground from the fuel heater connector
to SP 6.
c. If the fuel heater temperature is below 45_F (7.2_C)
replace the fuel heater. If the fuel heater temperature
is above 45_F (7.2_C), the internal temperature
switch may be open. Retest at a temperature below
the switch close point as soon as conditions allow.
8.5.8 Engine Oil And Oil Filter
a. To Check The Engine Oil Level:
1 Warm up the engine and then stop it by placing the
Main Power switch in the OFF position. Ensure the
unit will not start automatically by disabling any two
way communication. Disconnect the high voltage
source and lockout/tagout the receptacle.