rear diff DODGE RAM 2001 Service Repair Manual

MESSAGE SYSTEMS
TABLE OF CONTENTS
page page
OVERHEAD CONSOLE
DESCRIPTION............................1
STANDARD PROCEDURE...................4
COMPASS CALIBRATION..................4
COMPASS VARIATION ADJUSTMENT........4
COMPASS DEMAGNETIZING...............5
REMOVAL...............................6
DISASSEMBLY............................7
ASSEMBLY..............................7
INSTALLATION............................8
SPECIAL TOOLS..........................8
COMPASS/MINI-TRIP COMPUTER
DESCRIPTION............................8OPERATION.............................9
DIAGNOSIS AND TESTING.................10
COMPASS MINI-TRIP COMPUTER..........10
REMOVAL..............................11
INSTALLATION...........................11
AMBIENT TEMP SENSOR
DESCRIPTION...........................11
OPERATION.............................11
DIAGNOSIS AND TESTING.................12
AMBIENT TEMPERATURE SENSOR........12
REMOVAL..............................12
INSTALLATION...........................13
OVERHEAD CONSOLE
DESCRIPTION
Two different overhead console units are available
factory-installed options on this model, base or pre-
mium. The base overhead console unit features a
garage door opener storage bin, a sunglasses storage
bin and two reading and courtesy lamps. The pre-
mium overhead console has all of the features of the
base unit, but adds a compass mini-trip computer.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of all of the overhead console components and sys-
tems. Refer toOverhead Consolein the Contents of
Wiring Diagrams for complete circuit diagrams.
The premium overhead console (Fig. 1) includes
two front-mounted reading and courtesy lamps, a
garage door opener storage bin, and a sunglasses
storage bin. The premium overhead console includes
a compass mini-trip computer. The base overhead
console uses the same overhead console housing, but
has a computer cover plug installed in place of the
compass mini-trip computer display module lens and
push buttons.
The rear of the overhead console is secured to two
rear mounting holes in the inner roof panel by two
plastic hook formations that are integral to the over-
head console housing. The front of the overhead con-
sole is secured to the two front mounting holes of the
inner roof panel by two plastic latches that are inte-
gral to the overhead console housing. A single electri-
cal connection joins the overhead console wireharness to the roof wire harness for both the base
and premium overhead console units.
Following are general descriptions of the major
components used in the overhead console. See the
owner's manual in the vehicle glove box for more
information on the use and operation of the various
overhead console features.
GARAGE DOOR OPENER STORAGE BIN
A compartment near the front of the overhead con-
sole is designed to hold most garage door opener
remote control transmitters. The transmitter is
mounted within the compartment with an adhesive-
backed hook and loop fastener patch and, when the
compartment is closed, a push button in the center of
the compartment door is depressed to actuate the
transmitter.
A transmitter mounting kit including the adhesive-
backed hook and loop fastener material is available
for service. The garage door opener storage bin door
and the push button with three assorted length
adapter pegs are also available for service replace-
ment.
The garage door opener storage compartment door
is opened by pressing the integral latch towards the
front of the vehicle. When the compartment door is
opened, the push button unit is removed from the
compartment by squeezing the latch tabs and pulling
the unit downward. With the push button removed,
the garage door opener can be installed in the com-
partment using the adhesive-backed hook and loop
fastener material provided.
BR/BEMESSAGE SYSTEMS 8M - 1

OPERATION
The ambient photocell sensor is located on the for-
ward-facing (windshield side) of the rear view mirror
housing, and detects the ambient light levels outside
of the vehicle. The headlamp photocell sensor is
located inside the rear view mirror housing behind
the mirror glass and faces rearward, to detect the
level of the light being received at the rear window
side of the mirror. When the circuitry of the auto-
matic day/night mirror detects that the difference
between the two light levels is too great (the light
level received at the rear of the mirror is much
higher than that at the front of the mirror), it begins
to darken the mirror.
The automatic day/night mirror circuitry also mon-
itors the transmission using an input from the
backup lamp circuit. The mirror circuitry is pro-
grammed to automatically disable its self-dimming
feature whenever it senses that the transmission
backup lamp circuit is energized.
The automatic day/night mirror is a completely
self-contained unit and cannot be repaired. If faulty
or damaged, the entire mirror assembly must be
replaced.
DIAGNOSIS AND TESTING - AUTOMATIC
DAY/NIGHT MIRROR
For circuit descriptions and diagrams, refer to the
appropriate wiring information. The wiring informa-
tion includes wiring diagrams, proper wire and con-
nector repair procedures, details of wire harness
routing and retention, connector pin-out information
and location views for the various wire harness con-
nectors, splices and grounds.
(1) Check the fuse in the junction block. If OK, go
to Step 2. If not OK, repair the shorted circuit or
component as required replace the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the junction
block. If OK, go to Step 3. If not OK, repair the open
circuit to the ignition switch as required.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Unplug the wire harness connector from the auto-
matic day/night mirror (Fig. 1). Connect the battery
negative cable. Turn the ignition switch to the On
position. Check for battery voltage at the fused igni-
tion switch output (run/start) circuit cavity of the
automatic day/night mirror wire harness connector. If
OK, go to Step 4. If not OK, repair the open circuit to
the junction block as required.
(4) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Check for continuity between the ground circuit cav-
ity of the automatic day/night mirror wire harness
connector and a good ground. There should be conti-nuity. If OK, go to Step 5. If not OK, repair the cir-
cuit to ground as required.
(5) Connect the battery negative cable. Turn the
ignition switch to the On position. Set the parking
brake. Place the transmission gear selector lever in
the Reverse position. Check for battery voltage at the
backup lamp switch output circuit cavity of the auto-
matic day/night mirror wire harness connector. If
OK, go to Step 6. If not OK, repair the open circuit
as required.
(6) Turn the ignition switch to the Off position.
Disconnect the battery negative cable. Plug in the
automatic day/night mirror wire harness connector.
Connect the battery negative cable. Turn the ignition
switch to the On position. Place the transmission
gear selector lever in the Neutral position. Place the
mirror switch in the On (LED in the mirror switch is
lighted) position. Cover the forward facing ambient
photocell sensor to keep out any ambient light.
NOTE: The ambient photocell sensor must be cov-
ered completely, so that no light reaches the sen-
sor. Use a finger pressed tightly against the sensor,
or cover the sensor completely with electrical tape.
(7) Shine a light into the rearward facing head-
lamp photocell sensor. The mirror glass should
darken. If OK, go to Step 8. If not OK, replace the
faulty automatic day/night mirror unit.
(8) With the mirror glass darkened, place the
transmission gear selector lever in the Reverse posi-
tion. The mirror should return to its normal reflec-
tance. If not OK, replace the faulty automatic day/
night mirror unit.
Fig. 1 Automatic Day/Night Mirror
BR/BEPOWER MIRRORS 8N - 11
AUTOMATIC DAY / NIGHT MIRROR (Continued)

DRIVER POWER SEAT SWITCH
DESCRIPTION
The power seat in standard cab models can be
adjusted in six different ways using the power seat
switches (Fig. 1). The power seat switch for extended
cab models (club cab and quad cab) has an additional
switch knob for adjusting the power lumbar support.
The switch is located on the lower outboard side of the
seat cushion on the seat cushion side shield on all mod-
els. Refer to the owner's manual in the vehicle glove box
for more information on the power seat switch functions
and the seat adjusting procedures.
The individual switches in the power seat switch
module cannot be repaired. If one switch is damaged
or faulty, the entire power seat switch module must
be replaced.
OPERATION
When a power switch control knob or knobs are actu-
ated, a battery feed and a ground path are applied
through the switch contacts to the power seat track or
recliner adjuster motor. The selected adjuster motor
operates to move the seat track or recliner through its
drive unit in the selected direction until the switch is
released, or until the travel limit of the adjuster is
reached. When the switch is moved in the opposite
direction, the battery feed and ground path to the motor
are reversed through the switch contacts. This causes
the adjuster motor to run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel limit.
The power seat adjuster motors each contain a self-re-
setting circuit breaker to protect them from overload.
However, consecutive or frequent resetting of the circuit
breaker must not be allowed to continue, or the motor
may be damaged.
DIAGNOSIS & TESTING - DRIVER POWER
SEAT SWITCH
For circuit descriptions and diagrams, refer to Wir-
ing Diagrams.
(1)
Disconnect and isolate the battery negative cable.
(2)Remove the power seat switch from the power
seat.
(3)Use an ohmmeter to test the continuity of the
power seat switches in each position. See the Power
Seat Switch Continuity chart (Fig. 2) . If OK, see Power
Seat Adjuster and Motors or Power Lumbar Adjuster
and Motor in the Diagnosis and Testing section of this
group. If not OK, replace the faulty power seat switch
unit.
DRIVER POWER SEAT SWITCH TEST TABLE
DRIVER SWITCH
POSITIONCONTINUITY BETWEEN
OFF B-N, B-J, B-M
B-E, B-L, B-K
VERTICAL UP A-E, A-M, B-N, B-E
VERTICAL DOWN A-J, A-N, B-M, B-E
HORIZONTAL
FORWARDA-L, B-K
HORIZONTAL
REARWARDA-K, B-L
FRONT TILT UP A-M, B-N
FRONT TILT DOWN A-N, B-M
REAR TILT UP A-E, B-J
REAR TILT DOWN A-J, B-E
LUMBAR OFF O-P, O-R, P-R
LUMPAR UP (INFLATE) O-P, Q-R
LUMBAR DOWN
(DEFLATE)O-R, P-Q
Fig. 1 Seat Switches and Bezel - Standard Cab
1 - Seat Switch
Fig. 2 Testing Driver Power Seat Switch
8N - 16 POWER SEAT SYSTEMBR/BE

PASSENGER POWER SEAT
SWITCH
DESCRIPTION
The power seat in standard cab models can be
adjusted in six different ways using the power seat
switches (Fig. 6). The power seat switch for extended
cab models (club cab and quad cab) has an additional
switch knob for adjusting the power lumbar support.
The switch is located on the lower outboard side of
the seat cushion on the seat cushion side shield on
all models. Refer to the owner's manual in the vehi-
cle glove box for more information on the power seat
switch functions and the seat adjusting procedures.
The individual switches in the power seat switch mod-
ule cannot be repaired. If one switch is damaged or
faulty, the entire power seat switch module must be
replaced.
OPERATION
When a power switch control knob or knobs are actu-
ated, a battery feed and a ground path are applied
through the switch contacts to the power seat track or
recliner adjuster motor. The selected adjuster motor
operates to move the seat track or recliner through its
drive unit in the selected direction until the switch is
released, or until the travel limit of the adjuster is
reached. When the switch is moved in the opposite direc-
tion, the battery feed and ground path to the motor are
reversed through the switch contacts. This causes the
adjuster motor to run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resettingof the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged.
DIAGNOSIS & TESTING - PASSENGER POWER
SEAT SWITCH
For circuit descriptions and diagrams, refer to Wir-
ing Diagrams.
(1)
Disconnect and isolate the battery negative cable.
(2)Remove the power seat switch from the power
seat.
(3) Use an ohmmeter to test the continuity of the
power seat switches in each position. See the Power
Seat Switch Continuity chart below (Fig. 7) . If OK,
see Power Seat Adjuster and Motors or Power Lum-
bar Adjuster and Motor in the Diagnosis and Testing
section of this group. If not OK, replace the faulty
power seat switch unit.
PASSENGER POWER SEAT SWITCH TEST TABLE
PASSENGER SWITCH
POSITIONCONTINUITY BETWEEN
OFF B-N, B-J, B-M,B-E, B-L,
B-K
VERTICAL DOWN A-E, A-M, B-N, B-E
VERTICAL UP A-J, A-N, B-M, B-E
HORIZONTAL
FORWARDA-L, B-K
HORIZONTAL
REARWARDA-K, B-L
FRONT TILT DOWN A-M, B-N
FRONT TILT UP A-N, B-M
REAR TILT DOWN A-E, B-J
REAR TILT UP A-J, B-E
LUMBAR OFF O-P, O-R, P-R
LUMBAR DOWN
(DEFLATE)O-P, Q-R
LUMBAR UP (INFLATE) O-R, P-Q
Fig. 6 Seat Switches and Bezel - Standard Cab
1 - Seat Switch
Fig. 7 Testing Passenger Power Seat Switch
BR/BEPOWER SEAT SYSTEM 8N - 19

the motor and drive unit of the power seat recliner
mechanism is secured with two screws to the seat
cushion frame, and is concealed by the outboard seat
cushion side shield.
The power seat recliner cannot be repaired. If the
unit is faulty or damaged, it must be replaced. Refer
toBucket Seat Reclinerin Body for the service
procedure.
OPERATION
The power seat recliner includes a reversible elec-
tric motor that is secured to the lower hinge plate of
the recliner unit. The motor is connected to a gearbox
that moves the upper hinge plate of the power seat
recliner through a screw-type drive unit.
DIAGNOSIS & TESTING - POWER SEAT
RECLINER
Following are tests that will help to diagnose the
hard wired components and circuits of the power seat
system. Actuate the power seat recliner switch to
move the power seat recliner adjuster in each direc-
tion. The power seat recliner adjuster should move in
both directions. If the power seat recliner adjuster
fails to operate in only one direction, move the
adjuster a short distance in the opposite direction
and test again to be certain that the adjuster is not
at its travel limit. If the power seat recliner adjuster
still fails to operate in only one direction, refer to
Power Seat Switchin the Diagnosis and Testing
section of this group. If the power recliner adjuster
fails to operate in either direction, perform the fol-
lowing tests. For complete circuit diagrams, refer to
Power Seatin Wiring Diagrams.
(1) Check the power seat circuit breaker in the
junction block. If OK, go to Step 2. If not OK, replace
the faulty power seat circuit breaker.
(2) Check for battery voltage at the power seat cir-
cuit breaker in the junction block. If OK, go to Step
3. If not OK, repair the open fused B(+) circuit to the
fuse in the Power Distribution Center as required.
(3) Remove the outboard seat cushion side shield
from the seat. Disconnect the seat wire harness con-
nector from the power seat switch connector recepta-
cle. Check for battery voltage at the fused B(+)
circuit cavity of the power seat wire harness connec-
tor for the power seat switch. If OK, go to Step 4. If
not OK, repair the open fused B(+) circuit to the
power seat circuit breaker in the junction block as
required.
(4) Check for continuity between the ground cir-
cuit cavity of the power seat wire harness connector
for the power seat switch and a good ground. There
should be continuity. If OK, go to Step 5. If not OK,
repair the open ground circuit to ground as required.(5) Test the power seat switch. Refer toPower
Seat Switchin the Diagnosis and Testing section of
this group. If the switch tests OK, test the circuits of
the power seat wire harness between the power seat
recliner adjuster motor and the power seat switch for
shorts or opens. If the circuits check OK, replace the
faulty power seat recliner unit. If the circuits are not
OK, repair the power seat wire harness as required.
POWER SEAT TRACK
DESCRIPTION
There are three reversible motors that operate the
power seat adjuster. The motors are connected to
worm-drive gearboxes that move the seat adjuster
through a combination of screw-type drive units.
The front and rear of a seat are operated by differ-
ent motors. They can be raised or lowered indepen-
dently of each other. When the center seat switch is
pushed in the Up or Down direction, both the front
and rear motors operate in unison. On standard cab
models the entire seat is moved up or down, on
extended cab models (club cab and quad cab) the seat
cushion moves independently of the seat back in the
up or down directions. The forward-rearward motor
is operated by pushing the center seat switch in the
Forward or Rearward direction, which moves the
entire seat in the selected direction on all models.
Each motor contains a self-resetting circuit breaker
to protect it from overload. Consecutive or frequent
resetting of the circuit breakers must not be allowed
to continue, or the motors may be damaged. Make
the necessary repairs.
The power seat adjuster and motors cannot be
repaired, and are serviced only as a complete unit. If
any component in this unit is faulty or damaged, the
entire power seat adjuster and motors assembly must
be replaced.
OPERATION
When a power seat switch is actuated, a battery
feed and a ground path are applied through the
switch contacts to the motor(s). The motor(s) and
drive unit(s) operate to move the seat in the selected
direction until the switch is released, or until the
travel limit of the power seat adjuster is reached.
When the switch is moved in the opposite direction,
the battery feed and ground path to the motor(s) are
reversed through the switch contacts. This causes the
motor to run in the opposite direction.
DIAGNOSIS & TESTING - POWER SEAT TRACK
For circuit descriptions and diagrams, refer to Wir-
ing Diagrams.
BR/BEPOWER SEAT SYSTEM 8N - 21
RECLINER MOTOR (Continued)

contains all of the switches for both the wiper and
washer systems.
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole on the
lower rear side of the washer reservoir, above the
washer pump/motor unit near the left front corner of
the engine compartment.
²Washer Nozzles- The dual fluidic washer noz-
zles are secured with integral snap features to dedi-
cated openings in the cowl plenum cover/grille panel
located near the base of the windshield. The washer
plumbing fittings for the washer nozzles are con-
cealed beneath the cowl plenum cover/grille panel.
²Washer Pump/Motor- The washer pump/mo-
tor unit is located in a dedicated hole on the lower
rear side of the washer reservoir near the left front
corner of the engine compartment.
²Washer Reservoir- The washer reservoir is
secured to the left side of the radiator fan shroud in
the left front corner of the engine compartment.
²Wiper Arms- The two wiper arms are secured
to the two wiper pivots, which extend through the
cowl plenum cover/grille panel located near the base
of the windshield.
²Wiper Blades- The two wiper blades are
secured to the two wiper arms, and are parked on
the glass near the bottom of the windshield when the
wiper system is not in operation.
²Wiper Module- The wiper pivots are the only
visible components of the wiper module. The remain-
der of the module is concealed within the cowl ple-
num beneath the cowl plenum cover/grille panel. The
wiper module includes the module bracket, the single
wiper motor, the wiper linkage, and the two wiper
pivots.
²Wiper Relay- The wiper relay is located in the
Power Distribution Center (PDC) in the engine com-
partment near the battery.
Features of the wiper and washer system include
the following:
²Continuous Wipe Modes- The two-speed
wiper motor and the internal circuitry of the multi-
function switch work in concert to provide two con-
tinuous wipe cycles, low speed or high speed.
²Intermittent Wipe Mode- The internal cir-
cuitry of the multi-function switch, the CTM, and the
wiper relay work in concert to provide an intermit-
tent wipe mode with multiple delay interval selec-
tions. On models with a high-line or premium CTM,
the CTM also automatically adjusts each manually
selected delay interval to compensate for vehicle
speed.
²Washer Mode- When the washer system is
activated with the multi-function switch while the
wiper system is operating, washer fluid will be dis-
pensed onto the windshield glass through the washernozzles for as long as the washer pump/motor is
energized.
²Wipe-After-Wash Mode- The internal circuitry
of the CTM provides a wipe-after-wash feature
which, if the wipers are turned Off, will operate the
washer pump/motor and the wipers for as long as the
washer system is activated, then provide several
additional wipe cycles after the washer system is
deactivated before parking the wiper blades near the
base of the windshield.
Hard wired circuitry connects the wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the wiper and washer
system components through the use of a combination
of soldered splices, splice block connectors, and many
different types of wire harness terminal connectors
and insulators. Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
further details on wire harness routing and reten-
tion, as well as pin-out and location views for the
various wire harness connectors, splices and grounds.
OPERATION
The wiper and washer system is intended to pro-
vide the vehicle operator with a convenient, safe, and
reliable means of maintaining visibility through the
windshield glass. The various components of this sys-
tem are designed to convert electrical energy pro-
duced by the vehicle electrical system into the
mechanical action of the wiper blades to wipe the
outside surface of the glass, as well as into the
hydraulic action of the washer system to apply
washer fluid stored in an on-board reservoir to the
area of the glass to be wiped. When combined, these
components provide the means to effectively main-
tain clear visibility for the vehicle operator by remov-
ing excess accumulations of rain, snow, bugs, mud, or
other minor debris from the outside windshield glass
surface that might be encountered while driving the
vehicle under numerous types of inclement operating
conditions. The vehicle operator initiates all wiper
and washer system functions with the multi-function
switch control stalk that extends from the left side of
the steering column, just below the steering wheel.
Rotating the knob on the end of the multi-function
switch control stalk selects the desired wiper system
operating mode. The wiper system allows the vehicle
operator to select from two continuous wiper speeds,
Hi or Lo, or one of several intermittent wipe Delay
mode intervals. Pushing the button on the end of the
control stalk downwards towards the steering column
8R - 2 WIPERS/WASHERSBR/BE
WIPERS/WASHERS (Continued)

DIAGNOSIS AND TESTINGÐREAR SEAL AREA
LEAKS
Since it is sometimes difficult to determine the
source of an oil leak in the rear seal area of the
engine, a more involved inspection is necessary. The
following steps should be followed to help pinpoint
the source of the leak.
If the leakage occurs at the crankshaft rear oil seal
area:
(1) Disconnect the battery.
(2) Raise the vehicle.
(3) Remove torque converter or clutch housing
cover and inspect rear of block for evidence of oil.
Use a black light to check for the oil leak:
(a) Circular spray pattern generally indicates
seal leakage or crankshaft damage.
(b) Where leakage tends to run straight down,
possible causes are a porous block, distributor seal,
camshaft bore cup plugs, oil galley pipe plugs, oil
filter runoff, and main bearing cap to cylinder
block mating surfaces.
(4) If no leaks are detected, pressurized the crank-
case as outlined in (Refer to 9 - ENGINE/LUBRICA-
TION - DIAGNOSIS AND TESTING)
CAUTION: Do not exceed 20.6 kPa (3 psi).
(5) If the leak is not detected, very slowly turn the
crankshaft and watch for leakage. If a leak is
detected between the crankshaft and seal while
slowly turning the crankshaft, it is possible the
crankshaft seal surface is damaged. The seal area on
the crankshaft could have minor nicks or scratches
that can be polished out with emery cloth.
CAUTION: Use extreme caution when crankshaft
polishing is necessary to remove minor nicks or
scratches. The crankshaft seal flange is specially
machined to complement the function of the rear oil
seal.
(6) For bubbles that remain steady with shaft
rotation, no further inspection can be done until dis-
assembled. Refer to the service DiagnosisÐMechani-
cal, under the Oil Leak row, for components
inspections on possible causes and corrections.
(7) After the oil leak root cause and appropriate
corrective action have been identified, (Refer to 9 -
ENGINE/ENGINE BLOCK/CRANKSHAFT OIL
SEAL - REAR - REMOVAL), for proper replacement
procedures.
STANDARD PROCEDUREÐCYLINDER BORE
HONING
Before honing, stuff plenty of clean shop towels
under the bores and over the crankshaft to keep
abrasive materials from entering the crankshaft
area.
(1) Used carefully, the Cylinder Bore Sizing Hone
C-823, equipped with 220 grit stones, is the best tool
for this job. In addition to deglazing, it will reduce
taper and out-of-round, as well as removing light
scuffing, scoring and scratches. Usually, a few strokes
will clean up a bore and maintain the required lim-
its.
CAUTION: DO NOT use rigid type hones to remove
cylinder wall glaze.
(2) Deglazing of the cylinder walls may be done if
the cylinder bore is straight and round. Use a cylin-
der surfacing hone, Honing Tool C-3501, equipped
with 280 grit stones (C-3501-3810). about 20-60
strokes, depending on the bore condition, will be suf-
ficient to provide a satisfactory surface. Using honing
oil C-3501-3880, or a light honing oil, available from
major oil distributors.
CAUTION: DO NOT use engine or transmission oil,
mineral spirits, or kerosene.
(3) Honing should be done by moving the hone up
and down fast enough to get a crosshatch pattern.
The hone marks should INTERSECT at 50É to 60É
for proper seating of rings (Fig. 3).
Fig. 3 Cylinder Bore Crosshatch Pattern
1 - CROSSHATCH PATTERN
2 - INTERSECT ANGLE
9 - 10 ENGINE 3.9LBR/BE
ENGINE 3.9L (Continued)

INSTALLATION
(1) Install the plunger, spring, and plug as shown
in (Fig. 152). Tighten the plug to 80 N´m (60 ft. lbs.)
torque.
(2) Connect the battery negative cables.
(3) Start the engine and verify that it has oil pres-
sure.
OIL PRESSURE SENSOR/
SWITCH
DESCRIPTION
The 3±wire, solid-state oil pressure sensor is
installed into the oil pressure galley on the engine
block. It is located below and to the rear of the
Engine Control Module (ECM) (Fig. 154).
OPERATION
Operation of the oil pressure sensor on the
diesel engine is controlled by the Engine Con-
trol Module (ECM). The Powertrain Control
Module (PCM) does not have any control over
the sensor.The oil pressure sensor uses three circuits. They
are:
²A 5±volt power supply from the ECM
²A sensor ground through the ECM's sensor
return
²A signal to the ECM relating to engine oil pres-
sure
The oil pressure sensor has a 3±wire electrical
function very much like the Manifold Absolute Pres-
sure (MAP) sensor on the gasoline powered engine.
Meaning different pressures relate to different output
voltages.
A 5±volt supply is sent to the sensor from the ECM
to power up the sensor. The sensor returns a voltage
signal back to the ECM relating to engine oil pres-
sure. This signal is then transferred (bussed) to the
instrument panel on the CCD bus circuit to operate
the oil pressure gauge and the check gauges lamp.
Ground for the sensor is provided by the ECM
through a low-noise sensor return.
REMOVAL
(1) Disconnect the battery negative cables.
(2) Disconnect the oil pressure sensor connector
(Fig. 155).
(3) Using a suitable socket, remove the oil pres-
sure sensor from the block (counter-clockwise).
Fig. 154 Oil Pressure Sensor (Engine) Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
Fig. 155 Oil Pressure Sensor Location
1 - ENGINE OIL PRESSURE SENSOR
2 - ELECTRIAL CONNECTOR
3 - ECM
9 - 298 ENGINE 5.9L DIESELBR/BE
OIL PRESSURE RELIEF VALVE (Continued)

DIMENSIONS FOR DIFFERING WHEELBASES*
WHEELBASE LENGTH
ALENGTH
BLENGTH
C
118 2118.0 3663.6 4185.4
134 2118.0 3994.5 4693.4
138 2626.0 4096.1 4693.4
154 2626.0 4502.5 5201.4
162 2118.0 4705.0 5042.5
*Measurements are in Millimeters (mm).
TORQUE SPECIFICATIONS
DESCRIPTION TORQUE
Cab Chassis adapter nut..... 108N´m(80ft.lbs.)
Front bumper brkt-to-frame nut . 68 N´m (50 ft. lbs.)
Front bumper outer brace bolt . . 68 N´m (50 ft. lbs.)
Rear bumper-to-brace nut..... 40N´m(30ft.lbs.)
Rear bumper brace-to-brkt nut . 101 N´m (75 ft. lbs.)
Rear bumper brkt-to-frame nut......... 101N´m
(75 ft. lbs.)
Skid plate crossmember-to-frame bolt..... 54N´m
(40 ft. lbs.)
Skid plate-to-crossmember bolt . 40 N´m (30 ft. lbs.)
Skid plate-to-trans crossmember bolt...... 54N´m
(40 ft. lbs.)
Spare tire winch bolt......... 27N´m(20ft.lbs.)
Trailer hitch nut............ 108N´m(80ft.lbs.)
CAB CHASSIS ADAPTER
BRACKET
REMOVAL
(1) Remove bolts attaching cab chassis adapter
brackets to frame rail (Fig. 11)
(2) Separate cab chassis adapter brackets from
frame rail
INSTALLATION
(1) Position cab chassis adapter brackets on frame
rail
(2) Install bolts attaching cab chassis adapter
brackets to frame rail.
FRONT TOW HOOK
REMOVAL
Some vehicles are equipped with front tow hooks.
The tow hooks are to be used forEMERGENCYpur-
poses only.(1) Remove the fasteners that attach the tow
hooks to the frame (Fig. 12).
(2) Separate the tow hooks from the frame.
Fig. 11 Cab Chassis Adapter Brackets
1 - ADAPTER BRACKETS
2 - FRAME
Fig. 12 Front Tow Hooks
1 - TOW HOOK
2 - FRAME
BR/BEFRAME & BUMPERS 13 - 9
SPECIFICATIONS (Continued)

(3) Installrearinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(4) Tighten fittings at fuel injector ends for cylin-
ders number 6 and 5 to 38 N´m (28 ft. lbs.) torque.
Do not tighten number 3 line at this time. It
will be tightened during bleeding procedure.
(5) Tighten 3 fittings at fuel injection pump ends
to 24 N´m (18 ft. lbs.) torque.
(6) Installfrontinjection line bundle beginning
with cylinder head (fuel injector) connections, fol-
lowed by injection pump connections. Tighten all fit-
tings finger tight.
(7) Tighten fitting at fuel injector end for cylinder
number 2 to 38 N´m (28 ft. lbs.) torque.Do not
tighten lines number 1 or 4 at this time. They
will be tightened during bleeding procedure.
(8) Tighten remaining 3 fittings at fuel injection
pump ends to 24 N´m (18 ft. lbs.) torque.
(9) Install fuel line support bracket bolts to intake
manifold and tighten to 24 N´m (18 ft. lbs.) torque.
CAUTION: Be sure fuel lines are not contacting
each other or any other component. Noise will
result.
(10) Install engine lifting bracket at rear of intake
manifold. Tighten 2 bolts to 77 N´m (57 ft. lbs.)
torque.
(11) Install cable bracket housing/cable assembly
and tighten 3 mounting bolts to 24 N´m (18 ft. lbs.)
torque.
(12) Clean any old gasket material below and
above intake manifold air heater element block. Also
clean mating areas at intake manifold and air intake
housing.
(13) Using new gaskets, position intake manifold
air heater element block to engine.
(14) Install air intake housing and position ground
cable. Install 4 mounting bolts and tighten to 24 N´m
(18 ft. lbs.) torque.
(15) Install air tube (intake manifold-to-charge air
cooler) (Fig. 41). Tighten clamps to 8 N´m (72 in. lbs.)
torque.
(16) Install engine oil dipstick tube support mount-
ing bolt and tighten to 24 N´m (18 ft. lbs.) torque.
(17) Install engine oil dipstick to engine.
(18) Connect 2 electrical cables to cable mounting
studs.
(19) Connect electrical connector to bottom of
APPS by pushing connector upward until it snaps
into position.
(20) Connect wiring harness (clip) at bottom of
Accelerator Pedal Position Sensor (APPS) mounting
bracket (Fig. 40).(21) Connect front wiring clip (Fig. 41) to cable
bracket housing.
(22) Install cable cover (Fig. 39).
(23) Connect both negative battery cables to both
batteries.
(24) Bleed air from fuel system. Do this at fuel
injector ends of lines. Use cylinders numbers 1, 3 and
4 for bleeding . (Refer to 14 - FUEL SYSTEM/FUEL
DELIVERY - STANDARD PROCEDURE). After
bleeding, tighten fittings to 38 N´m (28 ft. lbs.)
torque.
(25) Check lines/fittings for leaks.
FUEL TANK
DESCRIPTION - DIESEL FUEL TANK
The fuel tank is similar to the tank used with gas-
oline powered models. The tank is equipped with a
separate fuel return line and a different fuel tank
module for diesel powered models. A fuel tank
mounted, electric fuel pump is not used with diesel
powered models. Refer to Fuel Tank Module for addi-
tional information.
For removal and installation procedures, refer to
Fuel Tank - Gasoline Engines.
FUEL TANK MODULE
DESCRIPTION
An electric fuel pump isnot usedin the fuel tank
module for diesel powered engines. Fuel is supplied
by the engine mounted fuel transfer pump and the
fuel injection pump.
The fuel tank module is installed in the top of the
fuel tank (Fig. 48). The fuel tank module (Fig. 48)
contains the following components:
²Fuel reservoir
²A separate in-tank fuel filter
²Rollover valve
²Fuel gauge sending unit (fuel level sensor)
²Fuel supply line connection
²Fuel return line connection
²Auxiliary non-pressurized fuel supply fitting
OPERATION
Refer to Fuel Gauge Sending Unit.
REMOVAL
(1) Drain and remove fuel tank. Refer to Fuel
Tank Removal/Installation.
(2) Thoroughly clean area around tank module at
top of tank.
14 - 78 FUEL DELIVERY - DIESELBR/BE
FUEL LINES (Continued)