RAM 2500 Truck 4WD L6-5.9L DSL Turbo VIN 6 (1999)
Fuel Gauge Sender: Description and Operation
FUEL GAUGE SENDING UNIT
The fuel gauge sending unit (fuel level sensor) is attached to the side of the fuel tank module. The sending unit consists of a float, an arm, and a
variable resistor (track). The resistor track is used to send electrical signals to the powertrain Control Module (PCM) for fuel gauge operation.
After this signal is sent to the PCM, the PCM will transmit the data across the CCD bus circuits to the instrument panel. Here it is translated into
the appropriate fuel gauge level reading.
As fuel level increases, the float and arm move up. This decreases the sending unit resistance, causing the fuel gauge to read full. As fuel level
decreases, the float and arm move down. This increases the sending unit resistance causing the fuel gauge to read empty.
FUEL TANK MODULE
An electric fuel pump is not used in the fuel tank module for diesel powered engines. Fuel is supplied by the engine mounted fuel transfer pump
and the fuel injection pump.
Top View Of Fuel Tank Module
The fuel tank module is installed in the top of the fuel tank. The fuel tank module contains the following components:
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Fuel reservoir
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A separate in-tank fuel filter
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Rollover valve
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Fuel gauge sending unit (fuel level sensor)
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Fuel supply line connection
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Fuel return line connection
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Auxiliary non-pressurized fuel supply fitting