Dodge ram truck 3500 1996 Service Manual page 715

B R 8W • 40 INSTRUMENT CLUSTER
8W - 40 -1
8W-40 I N S T R U M E N T CLUSTER
INDEX
page
DESCRIPTION AND OPERATION
ABS WARNING LAMP 2
AIRBAG WARNING LAMP 3
ENGINE COOLANT TEMPERATURE GAUGE 1
FOUR-WHEEL DRIVE INDICATOR . . . . . . . . 3
FUEL GAUGE . . • . 1
GENERATOR LAMP 3
HELPFUL INFORMATION
3
HIGH-BEAM INDICATOR LAMP
2
INTRODUCTION . . 1
LOW FUEL WARNING LAMP . 2
LOW WASHER FLUID LAMP . . 2
MALFUNCTION INDICATOR LAMP (MIL)
2
D E S C R I P T I O N A N D O P E R A T I O N
INTRODUCTION
The instrument cluster contains the . gauges., and
warning lamps. A l l gauges have magnetic move­
ments.
When the' ignition switch is in the START or RUN
position, circuit A21 feeds circuit F14 through a bus
bar in the fuse block and fuse 12. Circuit A l from
fuse 3 in the Power Distribution Center (PDC) sup­
plies voltage to circuit A21.
Circuit F14 provides battery voltage for the warn­
ing lamps (except seat belt indicator lamp), transmis­
sion up shift lamp, and all gauges.
Circuit E2 from fuse 13 in the fuse block feeds the
illumination lamps. Circuit E l from the headlamp
switch powers fuse 13 when the parking lamps or
headlamps are ON.
Circuit Z3 provides ground for the indicator lamps
and illumination lamps. Circuit Z l l provides the
ground path for the gauges.
SPEEDOMETER
The speedometer and odometer receive a signal
from the Vehicle Speed Sensor (VSS) on circuit G7.
Circuit G7 is spliced and also connects to the Power-
train Control Module (PCM).
Circuit F14 from the fuse block provides voltage for
the speedometer. Circuit Z l l provides ground for the
speedometer.
FUEL GAUiE
Circuit G4 connects the fuel level sensor to the fuel
gauge in the instrument cluster. Circuit F14 from
fuse 12 in fuse block supplies voltage to the fuel
page
MANUAL TRANSMISSION UP-SHIFT LAMP
3
OIL PRESSURE GAUGE 2
OIL PRESSURE WARNING LAMP
2
PARKING BRAKE LAMP 3
SEAT BELT INDICATOR WARNING LAMP . . . . . . 2
SERVICE REMINDER INDICATOR (SRI) LAMP . . 3
SPEEDOMETER 1
TACHOMETER
2
TURN SIGNAL INDICATOR LAMPS
2
VOLTMETER
2
SCHEMATICS AND DIAGRAMS
WIRING DIAGRAM INDEX 3
gauge. The fuel level sensor draws voltage from cir­
cuit F14 through the fuel gauge on circuit G4. The
fuel level sensor is located in the fuel tank.
As current flows through the coils in the fuel
gauge, i t 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 the second coil in the fuel gauge. A change in
current flow alters the magnetic field in the fuel
gauge, which changes the pointer position.
Circuit Z l l provides the ground path for the fuel
level sensor.
ENGINE COOLANT TEMPERATURE GAUGE
Circuit G20 connects the engine coolant tempera­
ture gauge to the engine coolant temperature sensor.
The sensor is a variable resistor and case grounded
to the engine on all engines except the 8.0L V-10.
The V-10 engine coolant temperature sensor has an
external ground. Circuit F14 from fuse 12 in the fuse
block connects to the instrument cluster and supplies
voltage for the gauge.
As current flows through the coils in the gauge, it
creates a magnetic field. One of the coils in the gauge
receives fixed current. The other coil is connected to
the temperature gauge on circuit G20. A change in
temperature changes the resistance in the sensor,
which alters the current flow through the second coil
in the gauge. A change in current flow alters the
magnetic field in the gauge, which changes the
pointer position.