Dodge RAM TRUCK 1500 1995 Service Manual page 575

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8W-30 FUEL/IGNITION—GASOLINE ENGINES 8W - 30 - 3
in the fuse block supplies battery voltage to the coil
side of the fuel pump relay. The Powertrain Control
Module (PCM) provides the ground path for the coil
side of the relay on circuit K51. Circuit K51 connects
to cavity 51 of the PCM connector.
When the PCM grounds the fuel pump relay and
the contacts close, they connect circuits A14 and A61.
Circuit A61 supplies power to the fuel pump motor.
HELPFUL INFORMATION
Along with supplying voltage to the fuel pump re­
lay contacts, circuit A14 splices to supply voltage to
the contact side of the ASD relay.
Circuit F18 splices to supply battery voltage to the
coil sides of the ASD relay and fuel pump relay.
FUEL PUMP MODULE
FUEL PUMP MOTOR
When the fuel pump relay contacts close, circuit
A14 connects to circuit A61. Circuit A61 supplies
voltage to the fuel pump motor. Circuit Z13 provides
ground for the fuel' pump motor.
"UEL LEWEL SENSOR
The fuel level sensor is a variable resistor. Circuit
G4 connects the fuel level sensor to the fuel gauge in
the instrument cluster. Circuit F14 from fuse 12 in
the fuse block supplies voltage to the fuel gauge. The
fuel level sensor draws voltage from circuit F14
through the fuel gauge on circuit G4. Circuit Zll pro­
vides the ground path for the fuel level sensor.
As current flows through the coils in the fuel
gauge, it creates a magnetic field. One of the coils in
the gauge receives fixed current. The other coil is
connected to the level sensor. The magnetic field con­
trols the position of the fuel gauge pointer.
The fuel level sensor contains a variable resistor.
As the position of the float arm on the fuel level sen­
sor changes, the resistor changes the current flow
through second coil" in the fuel gauge. A change in
current flow alters the magnetic field in the fuel
gauge, which changes the pointer position. •
IDLE AIR CONTROL (IAC) MOTOR
The Powertrain Control Module (PCM) operates
the Idle Air Control (IAC) motor through 4 circuits -
K39, K40, K59, and K60. Each circuit connects to
separate cavities in the PCM connector.
• Circuit K39 connects to cavity 39 of the PCM con­
nector.
• Circuit K40 connects to cavity 40 of the PCM con­
nector.
• Circuit K59 connects to cavity 59 of the PCM con­
nector.
• Circuit K60 connects to cavity 60 of the PCM con­
nector.
VEHICLE SPEED SENSOR
Circuit K7 supplies 8 volts from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
The K7 circuit connects to cavity 7 of the PCM con­
nector.
Circuit G7 from the vehicle speed sensor provides
an input signal to the PCM. The G7 circuit connects
to cavity 47 of the PCM connector.
The PCM provides a ground for the vehicle speed
sensor signal (circuit G7) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM connector.
HELPFUL INFORMATION :
• Circuit G7 splices to the speedometer.
• Circuit K7 splices to supply 8 volts to the camshaft
position sensor, crankshaft position sensor, and Igni­
tion Control Module (ICM).
Circuit K4 splices to supply ground for the signals
from the following:
® Heated oxygen sensor(s)
• Camshaft position sensor
• Crankshaft position sensor
• Throttle position sensor
• Manifold absolute pressure sensor
• Engine coolant temperature sensor
• Intake air temperature sensor
HEATED OXYGEN SENSOR—V-6 AND LIGHT DUTY
V-8 ENGINES
When the Powertrain Control Module (PCM)
grounds the Automatic Shut Down (ASD) relay, the
contacts close and connect circuits A14 and A142.
Circuit A142 supplies battery voltage to the heated
oxygen sensor.
Circuit K41 delivers the signal from the heated ox­
ygen sensor to the PCM. Circuit K41 connects to cav­
ity 41 of the PCM.
The PCM provides a ground for the heated oxygen
sensor signal (circuit K41) through circuit K4. Circuit
K4 connects to cavity 4 of the PCM connector. Circuit
Zll provides a ground for the heater circuit in the
sensor.
HEATED OXYGEN SENSORS—HEAVY DUTY V-8
ENGINES AND V-10 ENGINES
The 8.0L V-10 engine uses two oxygen sensors, one
in each exhaust down pipe. When the Powertrain
Control Module (PCM) grounds the Automatic Shut
Down (ASD) relay, the contacts close and connect cir­
cuits A14 and A142. Circuit A142 supplies battery
voltage to the heated oxygen sensors.
Circuit K41 delivers the signal from the right
heated oxygen sensor to the PCM. Circuit K41 con­
nects to cavity 41 of the PCM.
Circuit K141 delivers the signal from the left
heated oxygen sensor to the PCM. Circuit K141 con­
nects to cavity 23 of the PCM.