1993 DODGE TRUCK fuel sending unit

• • ^ ^ ^ INSTRUMENT PANEL AND GAUGES 8E - 1
CONTENTS

page
CLUSTER AND GAUGE SERVICE PROCEDURES . 12
CLUSTER AND GAUGE TEST PROCEDURES .. i
GENERAL INFORMATION . 1
page

MESSAGE CENTER-DIESEL ENGINE ........ 4
MESSAGE CENTER-GAS ENGINE .......... 3

SWITCH
AND PANEL COMPONENT SERVICE . 16
GENERAL
INFORMATION
INDEX

page

Generator
Indicating
System
2
Distance
Sensor
2

Electronic
Digital
Clock
3

Fuel
Level
Indicating
System
1
page

Malfunction
Indicator
(Check
Engine)
3

Oil
Pressure
Warning
Lamp
................. 2
Speedometer/Odometer
System
2

Temperature
and Oil
Indicating
System
......... 2
D-body trucks have an instrument cluster which
includes gauges for fuel level, coolant temperature,
oil pressure, and charging system voltage (Fig. 1).
When the ignition switch is in the OFF position all
the gauges will show a reading except the voltage gauge. However, the readings are only accurate
when the ignition switch is in the ON position.
The cluster also includes warning lamps for:
• seat belt warning
• low oil pressure
• high beam
• left and right turn signals
• check engine. J908E-66

Fig.
11nstrument
Cluster
FUEL LEVEL INDICATING SYSTEM (FIG. 2)
A hinged float arm in the fuel tank raises or lowers
depending on the fuel level. The float arm contacts a
variable resistor in the gauge sending unit. This pro­
vides a change of resistance in the fuel gauge circuit
with any up or down movement of the float. This sender
resistance is shown as fuel level on the gauge. Resistance is greatest when the fuel level in the
tank is low and the float arm drops. With high resis­
tance current flow is low and consequently positions
the instrument panel gauge pointer to low.
Resistance in the circuit is at a minimum when the
tank is full and the float arm is raised. With resis­
tance at a minimum, current flow is high registering
full on the instrument panel gauge.
12
VOLTS
TO

GAUGE
IP

FUEL
TANK

SENDING
UNIT

FLOAT

SENDING
UNIT
1:
1
j
^
fCONNECTOR

!g|yj-»—
FUEL

GAUGE

FUEL

TANK

J098E-47

Fig.
2
Fuel
Level
Indicating
System

INSTRUMENT PANEL AND GAUGES

•

INSTRUMENT PANEL
AND
GAUGES
8E - 5
CLUSTER
AND
GAUGE TEST
PROCEDURES

INDEX
page
Fuel Gauge
Circuit
Test
9

Fuel Tank Sending
Unit
Test
5

Oil Pressure Gauge
Circuit
Test
..............
9
Sending
Unit
(Sensor) Test
5
page
Speedometer
10

Temperature
Gauge
Circuit
Test
8
Voltage Gauge
Circuit
Test
10

Warning Lamp System Tests
6

CAUTION:
Disconnect
battery
negative cable,
in
en­

gine compartment, before servicing instrument panel. When power
is
required
for
test purposes,
connect
battery
cable
(for
test only).

Disconnect battery negative cable after test
and before continuing service procedures.

SENDING
UNIT
(SENSOR) TEST
When
a
problem occurs with
a
cluster gauge,
be­

fore disassembling
the
cluster
to
check
the
gauge, check
for a
defective sending unit (sensor)
or
wiring.
(1) Sending units
and
wiring
can be
checked
by

grounding
the
connector leads,
at the
sending unit,
in
the
vehicle.

CAUTION:
When connecting
an
input
terminal
to

ground,
Do Not
leave
the
connection grounded
for
more than
a
few
seconds.

(2) With
the
ignition
in the ON
position;
a

grounded input will cause
the oil,
fuel
or
tempera­
ture gauge
to
read
at or
above maximum.
FUEL TANK SENDING
UNIT
TEST

(1) Disconnect wire from terminal
on
fuel tank
sending unit (Fig.
1).

FUEL PUMP SUPPLY
INPUT
TO
GAUGE
SENDING
UNIT
GROUND
FUEL PUMP GROUND
J928E-49

Fig.
1
Fuel
Tank
Sending
Connector
Terminals
(2) Connect wire
to a
known good sending unit.
(3) Connect
a
jumper wire between sending unit
fuel pick
up
tube
and a
good ground.
(4) Check fuel gauge
as
described
in
following

steps.
Allow
at
least three minutes
at
each test point
for gauge
to
settle. Lightly tapping instrument clus­
ter
may
help position pointer.

FUEL GAUGE SYSTEM DIAGNOSIS
FUEL GAUGE SYSTEM DIAGNOSIS FUEL GAUGE

DOES
NOT

READ
FULL FAULTY PRINTED
CIRCUIT BOARD FUEL GAUGE
INOPERATIVE OR ERRATIC FUEL GAUGE
INACCURATE

E

1

I

CHECK
FAULTY WIRING
OR
TANK DEFORMED
TANK
NOT
FULL COMPONENTS
CHECK
CHECK
ALL WIRING INCLUDING GROUND
i

FAULTY FUEL GAUGE SENDING
UNIT
i 1
FUEL
C
1
DOES
1
READ
1
pAUGE
I

>N0?
1

EMPTY
1

r

TANK
NOT
EMPTY
CHECK
PROPER
ALIGNMENT
OF PICKUP AND

SENDER
ASSEMBLY.

REFER
TO
GROUP
14
FAULTY FUEL
GAUGE

J908E-74

8E
- 6
INSTRUMENT PANEL
AND
GAUGES

•
(5)
Clip float arm of sending unit to its empty stop
(Fig. 2) and turn ignition key to ON position. The
gauge should read Empty, plus one pointer width, or
minus two pointer widths.
(6) Move and clip sending unit float arm to full

stop.
The gauge should read Full, or above.
Fig. 2 Fuel Tank Sending Unit Test
RESULTS (1) If fuel gauge does not meet specifications, check
following items as possible causes; (a) Wiring and connections between the gauge
sending unit and multiple connector. (b) Wiring and connections between multiple
connector and printed circuit board terminals.
(c) Circuit continuity between printed circuit
board terminals and gauge terminals.
If these items check okay, fuel gauge is defective
and must be replaced.
(2) If the fuel gauge meets specifications check fuel
tank and original installed fuel tank sending unit as follows:
(a) Carefully remove fuel tank sending unit from
tank.
(b) Connect sending unit wire and jumper wire
as described in the procedure.
(3) If fuel gauge now checks within specifications,
originally installed sending unit is electrically okay,
check following as possible cause:
(a) Ground strap from sending unit to fuel line
for continuity. (b) Sending unit deformed. Make sure sending
unit float arm moves freely and pick up tube is not
bent so that it contacts bottom of tank. Inspect float for any signs of damage or leaks. (c) Sending unit improperly installed. Install
properly.
(d) Mounting flange on fuel tank for sending
unit deformed. Feel for interference fit of sending
unit to bottom of tank. It is permissible to bend
pick up tube down a little near mounting flange to gain interference fit.
(e) Fuel tank bottom deformed causing improper
positioning of sending unit pick up tube. Replace or
repair tank and recheck sending unit. Refer to Fuel
Tank Section of Group 14 - Fuel System.

WARNING
LAMP
SYSTEM
TESTS
LOW
OH.
PRESSURE WARNING LAMP CIRCUIT
TEST
The low oil pressure warning lamp will illuminate
when the ignition key is turned to the ON position.
The lamp also illuminates if the engine oil pressure drops below a safe oil pressure level.
To test the system turn ignition key to the ON po­
sition.
If the lamp fails to light, inspect for a broken or
disconnected wire at the oil pressure combination
unit. The combination unit is located at the rear of
the engine (Fig. 3). If the wire at the connector checks good, pull connector loose from the switch and
with a jumper wire ground connector to the engine (Fig. 4). With the ignition key turned to the ON po­
sition check the warning lamp. If lamp still fails to
light, inspect for a burned out bulb or disconnected
socket in the cluster.
If light comes on, proceed and start engine. If the
lamp remains on, immediately turn engine off and
check engine oil pressure according to procedures as
outlined in Group 9 - Engine of this manual. If the
oil pressure meets specifications, check for a
grounded wire and/or replace the oil pressure send­
ing unit (refer to combination oil unit test). Fig. 3 Oil Pressure Sending Unit—Gas Engine

INSTRUMENT
PANEL
AND
GAUGES
8E - S
J938E-34
Fig. 7 Coolant Temperature Sensor—Gas Engine
AIR
TEMPERATURE SWITCH

-
COOLANT TEMPERATURE
SWITCH

Fig. 8 Coolant Temperature Sensor—Diesel Engine

OIL PRESSURE
GAUGE
CIRCUIT
TEST
(1) Remove oil pressure gauge. Refer to Gauge Re­
placement. (2) Check for continuity in the wire between the
oil pressure sensor and the oil pressure gauge (sensor
input pin) (Figs. 10, 11, 12 and 13). (3) With the ignition switch in the ON position,
check for battery voltage across the B+ pin and the Ground pin. J908E-6i_
Fig. 9 Temperature Gauge Pins

TEMPERATURE/OIL/FUEL
GAUGE
DIAGNOSIS

GAUGE INDICATES HIGHER

OR
LOWER
THAN
ACTUAL I
FAULTY WIRING
FAULTY SENDING
UNIT*

FAULTY INSTRUMENT PANEL
GAUGE*
ERRATIC
GAUGE OPERATION
'TEST

PROCEDURES

DESCRIBED

ARE
IN
APPROPRIATE
SECTION OF

SERVICE

MANUAL

LOOSE
OR DIRTY ELECTRICAL CONNECTIONS FAULTY INSTRUMENT PANEL
GAUGE*
J908E-52

FUEL
GAUGE
CIRCUIT
TEST
(1) Remove fuel gauge assembly. Refer to Gauge
Replacement. (2) Check for continuity in the wire between the
fuel tank sending unit and the gauge (fuel level in­
put pin) (Figs. 14 and 15). (3) With the ignition switch in the ON position,
check for battery voltage across the B + pin and the Ground pin.

8E
- 10
INSTRUMENT
PANEL
AND
GAUGES

GROUND
OIL
PRESSURE

SENSOR
INPUT

J908E-70

Fig.
10 Oil Pressure
Sending
Unit—Gas Engine

STEERING
PUMP
ENGINE
BLOCK

J9119-74

Fig.
11 Oil Pressure
Sending
Unit—Diesel Engine
SENDING
UNIT
(GAUGE)

SWITCH
(LIGHT)
898E-2

Fig.
12 Combination Oil Unit Terminals

VOLTAGE
GAUGE
CIRCUIT
TEST
(1) Remove voltage gauge. Refer to Gauge Replace­
ment.
Fig.
13 Oil Pressure
Gauge
Pins

r— FUEL
PUMP
SUPPLY

0 INPUT TO
GAUGE
-SENDING
UNIT
GROUND

-FUEL
PUMP
GROUND
J928E-49

Fig.
14 Fuel Tank
Sending
Connector Terminals

FUEL
GAUGE
INPUT

^
GROUND
y
J908E-71

Fig.
15 Fuel
Gauge
Pins

(2) With the ignition switch in the ON position,
check for battery voltage across the B+ pin and the Ground pin (Fig. 16).
The instrument panel voltmeter indicates elec­
trical system battery voltage.

SPEEDOMETER
(1) Remove speedometer assembly. Refer to Gauge
Replacement.

FUEL
INJECTOR
#6
FUEL
INJECTOR
#4
FUEL
INJECTOR
#2
BEYOND
THIS
POINT

SEE
VIEW
Z

EGR
SOLENOID/
TRANSDUCER
ASSEMBLY
A/C
COMPRESSOR

CLUTCH

GENERATOR
GROUND
POWER
STEERING
PUMP

AAAP

SENSOR
THROTTLE
EVAP/

POSITION
PURGE
(SENSOR)
SOLENOID IDLE
AIR

CONTROL MOTOR
TO
A/C

COMPRESSOR
CLUTCH
DISTRIBUTOR

IGNITION
COIL
ENGINE

COOLANT

TEMPERATURE

ENGINE
COOLANT
SENSOR
(PCM)
TEMPERATURE

SENSOR
(GAUGE)
ENGINE
OIL

PRESSURE

SENDING
UNIT/
SWITCH
DISTRIBUTOR

CONNER ,NJECTOR#1
INJECTOR
#3
VIEW
IN
DIRECTION OF ARROW
1
FUEL
INJECTOR
#5
TO

'TRANSMISSION
WIRING

J938W-85 INS
m
a

o

>

o

>
2

m Fig. 23 Engine
Wiring
3.9L MPI Engine

FUEL
INJECTOR
#8
FUEL
INJECTOR #4 FUEL
INJECTOR
#2

EGR

SOLENOID/

TRANSDUCER

DISTRIBUTOR
IGNITION
COIL
THROTTLE

BODY

CHARGE
AIR

TEMPERATURE
SENSOR

BEYOND
THIS
POINT
SEE
VIEW,
Z

TO
A/C

COMPRESSOR
CLUTCH ^DISTRIBUTOR

GENERATOR
GROUND

POWER

STEERING
PUMP ENGINE
OIL

PRESSURE
SENDING
UNIT/SWITCH

VIEW
IN
DIRECTION OF ARROW
Y

TO TRANSMISSION WIRING

THROTTLE
POSITION
(SENSOR)
IDLE AIR
CONTROL MOTOR

GENERATOR
ENGINE COOLANT

TEMPERATURE
SENSOR
(PCM)
ENGINE
COOLANT

TEMPERATURE

SENSOR
(GAUGE)
MAP

SENSOR

FUEL
INJECTOR
#3

EVAP/PURGE

SOLENOID

FUEL
INJECTOR #7
FUEL
INJECTOR.
#5

FUEL
INJECTOR
#1

A/C
CLUTCH VIEW
IN
DIRECTION
OF ARROW
Z

J938W-86
Fig.
24 Engine Wiring 5.2L and 5.9L MPI Engine o
>
30

>

2
w

oo !\3

8W
- 38
WIRING
DIAGRAMS

• Wiring Diagram Name Sheet Number

EMCC
Relay
11

EMCC
Solenoid
11

Ground
11

EMCC
Relay
with Gas
Engine
11,16

EMCC
Solenoid
with Gas
Engine
11,12

Engine
Oil
Pressure Sending
Unit
.27,28
Engine
Starter
Motor
7,9
Engine
Starter
Relay
.7,9

Engine
Starter
System 1,7,8,9 Back-Up Lamp
Switch
.7,9

Bypass
Jumper
(Clutch
Pedal
Position)
8

Clutch
Pedal
Position
Switch
8

Fuse
. 7,9

Motor
7,9
Park/Neutral
Position
Switch
. .7,9

Relay
7,9

Engine Temp Sending
Unit
.
.27,28
Flasher-Hazard Warning
.56
Flasher-Turn Signal
56

Four Wheel
Drive
Indicator
Lamp
13

Front
End
Lighting
. .
.43,44

Front
End
Lighting
(Canada) 45,46

Fuel
Gauge
81,82

Fuel
Tank Gauge
Level
Sending
Unit
Diesel Engine
77

Fuel
Tank Gauge
Level
Sending
Unit
with Gas
Engine
78
Fuel
Heater
Diesel Engine
24

Fuel
Solenoid Diesel Engine
.24

Fuse
Application
Chart
1,2

Fuse
Block Module
and
Relay Bank
82

Fuses
Fuse
1 2,36
Fuse
2
.........
2,10,12,13,14,58,77,78

Fuse
3
2,7,9,10,39
Fuse
4
1,30,47

Fuse
5
1,77,78
Fuse
6
......
.1,73

Fuse
7
1,10,52

Fuse
8
.2,10,61,63
Fuse
9
.2,10,31,33,56

Fuse
10
.2,10,54,55

Fuse
11
2,10,66,67,69

Fuse
12
2,10,71
Fuse
13 1,56
Fuse
14
1,47,52,61,63

Fuse
15
1,49,51,52,61,63,75
Fusible Links 1,2,3,4,5,6,21

Gas
Engine
Wiring
Connector
89

Gauge-Fuel .77,78

Generator
.4,6

Glove
Box
Lamp
Switch
52

Hazard Warning System
. .56
Headlamp Dimmer
Switch
47

Headlamp
Switch
1,47

Headlamp
Switch
Controlled
Interior
Lamps
Headlamps 43,44,

Heated
Rear Window
(Sport
Utility)
Heater
Motor
Resistor

Heater
System Wiring Diagram Name Sheet Number
Horn System
30
Identification
Lamps-Dual Rear Wheels
41,42

Identification
Lamps-Roof Mounted
. 40
Ignition
Coil
.16

Ignition
Switch
.2,10

Ignition
Switch
System
10

Ignition
System (Gas Engine)
.........
.15,16,17,18,19,20
Automatic
Shut Down Relay
.16
Camshaft
Position
Sensor
20

Crankshaft
Position
Sensor
.18

Data
Link
Connector
* . . .17
Engine Coolant Temp
Sensor
20

EVAP
Purge Solenoid
16
Exhaust Gas
Recirculation
Solenoid
16
Fuel
Pump Relay
.16

Heated
Oxygen
Sensor
. . . 17

Idle
Air
Control
Motor
.19

Ignition
Coil
.15
Injectors
.15

Intake
Air
Temp
Sensor
. .20

Map
Sensor
. .20
Powertrain
Control
Module .15,16,17,18,19,20

Throttle
Position
(Sensor)
.18

Vehicle
Speed
Sensor
.20

Ignition
Time
Delay Relay
49

Injectors
.15 Intermittent
Wiper
System .53,54
Control
Unit
.54 Intermittent
Windshield
Wiper
Motor
54

Windshield
Washer Pump
Motor
53

Wiper
Switch
53

Key-In
Switch
49

Key-In Warning Buzzer 77,78
Lamps
Air-Conditioning
and
Heater
Switch
Lamp
48

Ash
Receiver .48,52 Back-Up Lamps
......
79,80,81
Cargo Lamp
.
.49,50 Clearance Lamps-Dual Rear Wheels .41,42
Clearance Lamps Roof Mounted
.40

Cluster
Illumination
Lamps
.
.57,58,59
Dome Lamp
50,51

Four Wheel
Drive
Indicator
.13

Glove
Box
Lamp
52
Headlamp-Left
43,45 Headlamp-Right 44,46
Headlamp
Switch
Controlled
Interior
Lamps
. 48

Heater
Switch
Lamp
.48
High Beam
Indicator
Lamp
.59

Identification
Lamp
.
.40,41

Ignition
Switch
Lamp
.49
Instrument
Panel
Illumination
Lamps
.
.57,58,59
License Lamp
. . . 80
.
.48 Low
Engine
Oil
Pressure Lamp
59

45,46
Map
Lamp
49

.
.39
Parking
Lamp-Left
Front
43,45
66,67 Parking Lamp-Right
Front
44,46 .
.66
Rear
End
Lighting
System .79,80,81