Chrysler RAM TRUCK 2500 1994 Service Manual page 955

14 - 14 FUEL SYSTEM
•
PRESSURE RELIEF/
ROLLOVER VALVE
PLASTIC
LOCKNUT
FRONT
OF TANK
AUX. FUEL
SUPPLY FITTING
FUEL
SUPPLY
UNE
FUEL
RETURN
UNE
FUEL GAUGE
SENDING
UNIT
ELECTRICAL
CONNECTOR
J9414-70
Fig. 2 Top View of Fuel Tank Module—Diesel
FLOAT
FUEL G A U G E LOCKING
SENDING UNIT TABS
ELECTRIC
FUEL PUMP
MOUNTING
SCREWS
IN-TANK
FUEL FILTER J9414-33
Fig. 3 Fuel Gauge Sending Unit—Typical
(4) The plastic locknut on the fuel tank module is
threaded onto the fuel tank. Remove the locknut
(Fig. 2). The tank module will spring up when the
locknut is removed.
(5) Remove module from fuel tank.
DISASSEMBLY—FUEL GAUGE SENDING UNIT
(1) Remove sending unit mounting screws (Fig. 3).
(2) Mark the sending unit electrical wires before
removal for correct installation. Carefully disconnect
electrical wires from sending unit. Remove sending
unit.
(3) Reverse order of removal for fuel gauge unit in­
stallation.
IN-TANK FUEL FILTER
The in-tank filter is attached to the bottom of the
fuel tank module (Fig. 3).
(1) Pry the mounting tabs back and remove the in-
tank fuel filter.
(2) Install new fuel filter into retaining tabs.
FUEL TANK MODULE INSTALLATION
CAUTION: Whenever the fuel tank module is ser­
viced, the locknut and rubber gasket must be re­
placed.
(1) Using a new gasket, position the fuel tank
module into the opening i n fuel tank. The fuel line
connectors, the pressure relief/rollover valve and the
fuel gauge electrical connector should all be pointed
to the drivers side of the vehicle before tightening
locknut.
(2) Position new locknut over top of fuel tank mod­
ule.
(3) Tighten locknut.
(4) Install fuel tank. Refer to Fuel Tank Installa­
tion i n this section.
AUXILIARY FUEL SUPPLY FITTING
An auxiliary (capped) fuel supply fitting is located
on the top of the fuel tank module (Fig. 2). This fit­
ting will be available only on: diesel powered models,
models with either a 5.9L V-8 heavy duty or 8.0L
V-10 engine and all cab-chassis models. This fitting
supplies a non-pressurized auxiliary fuel source.
FUEL HEATER
The fuel heater is used to prevent diesel fuel from
waxing during cold weather operation. The fuel
heater is located on the left side of the engine above
the starter motor (Fig. 4).
The heater assembly is equipped with a built-in
sensor (thermostat) (Fig. 4) that senses fuel temper­
ature. When the temperature is below 40 degrees F,
the built-in sensor allows current to flow to the
built-in heater element warming the fuel. When the
temperature is above 80 degrees F, the sensor stops
current flow to the heater element.
Voltage to operate the fuel heater is supplied from
the ignition switch and through the fuel heater relay
(Fig. 5) (also refer to Fuel Heater Relay).
The fuel heater and fuel heater relay are not con­
trolled by the powertrain control module (PCM).
The built-in heater element operates on 12 volts,
300 watts at 0 degrees F.
The fuel heater assembly contains a pre-filter to
prevent contaminants from entering the fuel transfer
pump.
For diagnosis, refer to the Diesel Engine—General
Diagnosis section of this group.
For removal and installation procedures, refer to
the Diesel Engine—Component Removal/Installation
section of this group.