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Electrical Maintenance
94
The wires in the fuel heater harness are connected
to the unit as follows.
•
The 2A wire is attached to the 2A (J25) screw
terminal on the base controller.
•
The 8FH-02 wire is connected to the 8FH-01
wire in the main/unified wire harness (inside
the control box), which is connected to pin 7
in the J16 connector on the base controller.
•
The CH wires are connected to the CH ground
plate behind the battery.
Diagnosis
Use the following procedure to diagnose the
electric fuel heater.
1. Disconnect the electric fuel heater from the
fuel heater harness at the 2-pin connector
located near the electric fuel heater.
2. Check the resistance of the electric fuel heater
by checking the resistance between the two
terminals in the 2-pin connector on the wires
to the electric fuel heater. The resistance
should be 0.9 to 1.1 ohms.
NOTE: The temperature of the electric fuel
heater must be below 30 F (-1 C) to verify the
internal thermostat closes.
•
If the resistance is acceptable, go to Step 3.
•
If the resistance is very high, indicating an
open circuit, check the temperature of the
electric fuel heater using a non-contact
thermometer. The temperature of the
electric fuel heater must be below 30 F
(-1 C) to close the internal thermostat. If
the temperature of the electric fuel heater
is below 30 F (-1 C) and high resistance
indicates an open circuit, the electric fuel
heater is probably defective and should be
replaced.
•
If the resistance is significantly less than
0.9 ohms, the heating element is probably
defective and the electric fuel heater
should be replaced.
NOTE: The unit must be turned on and running
in Diesel Mode for the rest of the procedure.
3. If the resistance of the electric fuel heater is
acceptable, turn the unit on and let the engine
start. Check the voltage between the 2HP and
CH wires in the fuel heater harness at the
2-pin connector that was disconnected from
the electric fuel heater in Step 1. Battery
voltage should be present between the 2HP
and CH wires.
4. If battery voltage is not present, check for
continuity to ground on the CH wire between
the 2-pin connector and the CH ground plate.
5. If the CH wire has good continuity to ground,
check for an open 2FH/2HP Fuse in the fuel
heater harness.
6. If the 2FH/2HP Fuse is not open, check the
continuity of the 2FH and 2HP wires between
the Fuel Heater Relay and the 2-pin connector.
1.
Fuel Filter Inlet
2.
Electric Fuel Heater Outlet
3.
Electric Fuel Heater Inlet
Figure 159: Electric Fuel Heater
ARA1962
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