Durango 4WD V8-5.9L VIN Z (1998)
Fuel Gauge: Description and Operation
SYSTEM OPERATION
The fuel gauge gives an indication of the level of fuel in the fuel tank. The instrument cluster circuitry controls the gauge pointer position. The
instrument cluster circuitry calculates the proper gauge pointer position based upon fuel level messages received from the Powertrain Control
Module (PCM) on the Chrysler Collision Detection (CCD) data bus.
The PCM uses an input from the fuel gauge sending unit and internal programming to decide what fuel level messages are required. The PCM then
sends the proper messages to the instrument cluster on the CCD data bus. If the PCM messages indicate that the fuel level is below one-eighth of a
full tank for more than ten seconds, the instrument cluster circuitry turns on the low fuel warning lamp and sends a chime tone request to the
Central Timer Module (CTM).
The fuel gauge sending unit is mounted to the electric fuel pump module located inside the fuel tank. The sending unit has a float attached to the
end of a swing-arm. The float moves up or down within the fuel tank as the fuel level changes. As the float moves, an electrical contact on the
pivot end of the swing-arm wipes across a resistor coil, which changes the internal electrical resistance of the sending unit.
