FUEL HEATER
DESCRIPTION
The fuel heater is incorporated within the Fuel Fil-
ter/Water Separator, which is located under the vehi-
cle in front of the rear axle assembly. It’s purpose is
to keep the fuel at a suitable temperature range to
improve cold starting, cold driveability and cold
exhaust emissions.
OPERATION
Fused battery positive voltage is supplied to the
fuel heater relay at all times through the Integrated
Power Module (IPM). Fused ignition positive voltage
is supplied to the fuel heater relay through the IPM.
The fuel heater is grounded through the ECM. When
the ignition switch is in Run or Start position, the
fuel heater relay contacts close and supply power to
the fuel heater. The fuel heater acts as a thermister
(resistance varies with temperature). If the fuel tem-
perature is 8°C (46°F) or below the heater turns on
until the temperature of the fuel reaches 25°C (76°F)
at which time the heater turns off. (Fig. 13).
Fig. 13 FUEL FILTER/WATER SEPARATOR
1 - FUEL/LIFT PUMP RETAINING BOLTS
2 - FUEL/LIFT PUMP
3 - FUEL FILTER/WATER SEPARATOR HOUSING
4 - FUEL HEATER
5 - CHECK BALL
6 - O-RING
7 - FLOW DIVERTER
8 - FUEL FILTER
9 - O-RING
10 - FUEL FILTER BOWL ASSEMBLY
RG
FUEL DELIVERY
14 - 15