Component Page
Overdrive Switch...................... 8W-31
Overhead Map/Reading Lamp............ 8W-44
Oxygen Sensors....................... 8W-30
Oxygen Sensor Downstream Relay........ 8W-30
Park Brake Switch.................... 8W-40
Park Lamp Relay................... 8W-50, 52
Park/Turn Signal Lamps............. 8W-50, 52
Passenger Airbag On/Off Switch.......... 8W-43
Blend Door Actuators.................. 8W-42
Passenger Lumbar Switch............... 8W-63
Power Mirrors........................ 8W-62
Power Outlet......................... 8W-41
Power Outlet-Console.................. 8W-41
Power Seat Motors.................... 8W-63
Power Seat Switches................... 8W-63
Power Steering Pressure Switch.......... 8W-30
Power Window Circuit Breaker........... 8W-10
Power Window Motors.................. 8W-60
Power Window Switches................ 8W-60
Powertrain Control Module.............. 8W-30
PTCs............................... 8W-10
PTO Switch.......................... 8W-30
Radio............................... 8W-47
Recirculation Door Actuator............. 8W-42
Red Brake Warning Indicator Switch . . . 8W-34, 35
Remote Radio Switches................. 8W-47
Splices.............................. 8W-70
Seat Belt Pretensioners................. 8W-43
Seat Belt Switch-Driver................ 8W-40
Seat Belt Tensioner Reducer............. 8W-40
Seat Heater Interface Module............ 8W-63
Sentry Key Immobilizer Module.......... 8W-39
Spare Relay.......................... 8W-10
Speakers............................ 8W-47Component Page
Speed Control Servo................... 8W-33
Speed Control Switches................. 8W-33
Starter Motor Relay................... 8W-21
Starter Motor.................... 8W-21, 21-3
Tail/Stop Lamps...................... 8W-52
Tail/Stop/Turn Signal Lamps.......... 8W-51, 52
Tail/Turn Lamps...................... 8W-52
Tailgate Lamp Assembly................ 8W-51
Throttle Position Sensor................ 8W-30
Throttle Position Switch................ 8W-30
Trailer Tow Connector.................. 8W-54
Trailer Tow Connector-Add On........... 8W-54
Trailer Tow Left Turn Relay............. 8W-54
Trailer Tow Right Turn Relay............ 8W-54
Transfer Case Control Module............ 8W-31
Transfer Case Mode Sensor.............. 8W-31
Transfer Case Selector Switch............ 8W-31
Transfer Case Shift Motor............... 8W-31
Transmission Control Module............ 8W-31
Transmission Control Relay............. 8W-31
Transmission Range Sensor.............. 8W-31
Transmission Solenoid Assembly.......... 8W-31
Transmission Solenoid/TRS Assembly...... 8W-31
Underhood Lamp...................... 8W-44
Vacuum Pump........................ 8W-30
Vehicle Speed Sensor................... 8W-30
Vistronic Fan Drive.................... 8W-30
Washer Fluid Level Switch.............. 8W-53
Washer Pump Motor-Front.............. 8W-53
Water In Fuel Sensor.................. 8W-30
Wheel Speed Sensors................... 8W-35
Wiper High/Low Relay................. 8W-53
Wiper Motor-Front.................... 8W-53
8W - 02 - 2 8W-02 COMPONENT INDEXDR
STANDARD PROCEDURE - REAR FRAME
H-SECTION REPLACEMENT
SAFETY PRECAUTIONS AND WARNINGS
WARNING: USE EYE PROTECTION WHEN GRIND-
ING OR WELDING METAL, SERIOUS EYE INJURY
CAN RESULT.
²BEFORE PROCEEDING WITH FRAME REPAIR
INVOLVING GRINDING OR WELDING, VERIFY THAT
VEHICLE FUEL SYSTEM IS NOT LEAKING OR IN
CONTACT WITH REPAIR AREA, PERSONAL INJURY
CAN RESULT.
²DO NOT ALLOW OPEN FLAME OR HEAT AND
METAL SPATTER FROM ARC WELDING, TO CON-
TACT PLASTIC BODY PANELS. FIRE OR EXPLO-
SION CAN RESULT.
²WHEN WELDED FRAME COMPONENTS ARE
REPLACED, ENSURE COMPLETE PENETRATION
WELD IS ACHIEVED DURING INSTALLATION. IF
NOT, DANGEROUS OPERATING CONDITIONS CAN
RESULT.
²STAND CLEAR OF CABLES OR CHAINS ON
PULLING EQUIPMENT DURING FRAME STRAIGHT-
ENING OPERATIONS, PERSONAL INJURY CAN
RESULT.
²DO NOT VENTURE UNDER A HOISTED VEHI-
CLE THAT IS NOT SUPPORTED ON SAFETY
STANDS, PERSONAL INJURY CAN RESULT.
CAUTION: Do not reuse damaged fasteners, quality
of repair would be suspect. Failure to use only pro-
duction fasteners or fasteners of equivalent hard-
ness can result in loosening or failure. Do not drill
holes in top or bottom frame rail flanges, frame rail
failure can result. When using heat to straighten
frame components do not exceed 566ÉC (1050ÉF),
metal fatigue can result.
CAUTION: This procedure is designed to replace
the H-section/spare tire support located at the rear
of the frame assembly. Prior to any cutting, the
vehicle must be mounted on the appropriate frame
repair equipment (ªframe rackº), checked with three
dimensional measuring equipment, and the neces-
sary pull corrections made. If damage remains in
the frame beyond the area covered by this service
part after the pull, the frame must be replaced in its
entirety.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cargo box. (Refer to 23 - BODY/EX-
TERIOR/CARGO BOX - REMOVAL)(3) Remove the trailer hitch. (Refer to 13 - FRAME
& BUMPERS/FRAME/TRAILER HITCH -
REMOVAL)
(4) Raise and support the frame so the tires are off
floor.
(5) Remove the shock absorbers. (Refer to 2 - SUS-
PENSION/REAR/SHOCK - REMOVAL)
(6) Remove the rear leaf spring shackle bolts and
let the axle rest on the ground. (Fig. 21)
(7) Remove the spare wheel.
(8) Remove the clip and remove the spare tire
winch tube. (Fig. 22)
Fig. 21 REAR SPRING
1 - SPRING SHACKLE
2 - LEAF SPRING EYE BOLT/NUT
3 - REAR LEAF SPRING
Fig. 22 SPARE TIRE WINCH TUBE
1 - SPARE TIRE WINCH ASSEMBLY
2 - HAIR PIN CLIP
3 - WINCH TUBE
4 - H-SECTION/SPARE WHEEL SUPPORT
DRFRAMES & BUMPERS 13 - 15
FRAME (Continued)
(9) Remove the bolts and remove the spare tire
winch. (Fig. 23)
(10) Position the wire harness forward of the work
area.
CAUTION: Do not use any flame or plasma cutting
equipment to cut the frame in this procedure. The
inaccurate and high temperatures achieved during
flame or plasma cutting will change the metal char-
acteristics and may weaken the frame and/or repair
location.
(11) Carefully remove the H-section welds using a
grinder or equivalent tool.
(12) Remove the H-section and clean any remain-
ing welds from the frame.
(13) Trial fit the replacement part.
(14) Remove all e-coat from within 25 mm (1.0 in.)
of the weld area.
(15) Using the appropriate measuring equipment,
position the replacement part and verify correct posi-
tioning in all three (X,Y, and Z) planes of space.(Refer to 13 - FRAME & BUMPERS/FRAME - SPEC-
IFICATIONS - FRAME DIMENSIONS)
CAUTION: Shield the surrounding area and compo-
nents from exposure to the welding spatter and
heat.
(16) Weld the replacement H-section into position.
The welding should be performed in a skip (stitch)
type method to minimize the heat buildup following
I-CAR or the American Welding Society welding pro-
cedures and utilizing the process specifications at the
end of this section. Refer to the Weld Process Speci-
fications welding schedule below.
(17) Dress the welded area and apply corrosion
resistant coatings inside and out.
(a) Inside the rail, inject a creeping wax based
rust inhibitor compound through the existing holes
in the frame ensuring 100% coverage including the
mating face between the frame and replacement
H-section.
(b) Apply a durable top coat to the outside of the
repair area.
(18) Position the wiring harness back.
(19) Install the spare tire winch and install the
bolts. (Fig. 23)
(20) Tighten the bolts to 41 N´m (30 ft. lbs.).
(21) Install the spare tire winch tube and install
the clip. (Fig. 22)
(22) Install the spare tire.
(23) Lift the axle into position and install the rear
shackle bolts. (Fig. 21)
(24) Tighten the bolts to 163 N´m (120 ft. lbs.).
(25) Install the lower shock absorber bolts. (Refer
to 2 - SUSPENSION/REAR/SHOCK - INSTALLA-
TION)
(26) Install the trailer hitch. (Refer to 13 - FRAME
& BUMPERS/FRAME/TRAILER HITCH - INSTAL-
LATION)
(27) Install the cargo box. (Refer to 23 - BODY/EX-
TERIOR/CARGO BOX - INSTALLATION)
(28) Reconnect the battery ground.
Fig. 23 SPARE TIRE WINCH ASSEMBLY
1 - SPARE TIRE WINCH ASSEMBLY
2 - BOLTS
3 - RETAINER BRACKET
4 - H-SECTION/SPARE WHEEL SUPPORT
13 - 16 FRAMES & BUMPERSDR
FRAME (Continued)
TIRES/WHEELS
TABLE OF CONTENTS
page page
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND
WHEEL RUNOUT......................1
STANDARD PROCEDURE
STANDARD PROCEDURE - TIRE ROTATION . 2
STANDARD PROCEDURE - MATCH
MOUNTING...........................3
STANDARD PROCEDURE - TIRE AND
WHEEL BALANCE......................4
TIRES
DESCRIPTION
DESCRIPTION - SPARE TIRE /
TEMPORARY.........................5
DESCRIPTION - TIRES..................5
DESCRIPTION - RADIAL ± PLY TIRES......6
DESCRIPTION - TIRE PRESSURE FOR
HIGH SPEEDS.........................6
DESCRIPTION - REPLACEMENT TIRES.....6
DESCRIPTION - TIRE INFLATION
PRESSURES..........................6
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - PRESSURE
GAUGES.............................7
DIAGNOSIS AND TESTING - TIRE NOISE
OR VIBRATION........................7
DIAGNOSIS AND TESTING - TREAD WEAR
INDICATORS..........................7
DIAGNOSIS AND TESTING - TIRE WEAR
PATTERNS...........................8
DIAGNOSIS AND TESTING - TIRE/VEHICLE
LEAD................................8STANDARD PROCEDURE - REPAIRING
LEAKS..............................10
SPECIFICATIONS
TIRE REVOLUTIONS PER MILE..........10
WHEELS
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING
WHEEL INSPECTION..................11
STANDARD PROCEDURE
STANDARD PROCEDURE - WHEEL
REPLACEMENT.......................12
STANDARD PROCEDURE - DUAL REAR
WHEEL INSTALLATION.................12
SPECIFICATIONS
TORQUE CHART......................13
STUDS
REMOVAL.............................14
INSTALLATION.........................14
WHEEL COVER
REMOVAL.............................14
INSTALLATION
INSTALLATION - REAR.................14
INSTALLATION - FRONT................15
SPARE TIRE
DESCRIPTION
DESCRIPTION - SPARE / TEMPORARY
TIRE...............................15
DESCRIPTION - FULL SIZE, SPARE WHEEL
WITH MATCHING TIRE.................15
TIRES/WHEELS
DIAGNOSIS AND TESTING - TIRE AND WHEEL
RUNOUT
Radial runout is the difference between the high
and low points on the tire or wheel (Fig. 1).
Lateral runout is thewobbleof the tire or wheel.
Radial runout of more than 1.5 mm (.060 inch)
measured at the center line of the tread may cause
the vehicle to shake.
Lateral runout of more than 2.0 mm (.080 inch)
measured near the shoulder of the tire may cause the
vehicle to shake.
Sometimes radial runout can be reduced. Relocate
the wheel and tire assembly on the mounting studs
(See Method 1). If this does not reduce runout to anacceptable level, the tire can be rotated on the wheel.
(See Method 2).
METHOD 1 (RELOCATE WHEEL ON HUB)
(1) Drive vehicle a short distance to eliminate tire
flat spotting from a parked position.
(2) Check wheel bearings and adjust if adjustable
or replace if necessary.
(3) Check the wheel mounting surface.
(4) Relocate wheel on the mounting, two studs
over from the original position.
(5) Tighten wheel nuts until all are properly
torqued, to eliminate brake distortion.
(6) Check radial runout. If still excessive, mark
tire sidewall, wheel, and stud at point of maximum
runout and proceed to Method 2.
DRTIRES/WHEELS 22 - 1
METHOD 2 (RELOCATE TIRE ON WHEEL)
NOTE: Rotating the tire on wheel is particularly
effective when there is runout in both tire and
wheel.
(1) Remove tire from wheel and mount wheel on
service dynamic balance machine.
(2) Check wheel radial runout (Fig. 2) and lateral
runout (Fig. 3).
²STEEL WHEELS: Radial runout 0.031 in., Lat-
eral runout 0.031 in. (maximum)
²ALUMINUM WHEELS: Radial runout 0.020 in.,
Lateral runout 0.025 in. (maximum)
(3) If point of greatest wheel lateral runout is near
original chalk mark, remount tire 180 degrees.
Recheck runout, Refer to match mounting procedure.
STANDARD PROCEDURE
STANDARD PROCEDURE - TIRE ROTATION
Tires on the front and rear axles operate at differ-
ent loads and perform different steering, driving, and
braking functions. For these reasons, the tires wear
at unequal rates. They may also develop irregular
wear patterns. These effects can be reduced by rotat-
ing the tires according to the maintenance schedule
in the Owners Manual. This will improve tread life,
traction and maintain a smooth quiet ride.
The recommended method of tire rotation is (Fig.
4) & (Fig. 5). Other methods can be used, but may
not provide the same tire longevity benefits.
CAUTION: 3500 Dual rear tires have a new tire rota-
tion pattern. This is to accommodate the asymmet-rical design of the ON/OFF road tires and the use of
the outlined white letter (OWL) tires. When replac-
ing a flat, the spare tire may have to be remounted
on the rim or installed at a different location to
maintain the correct placement of the asymmetrical
design or the (OWL).
Fig. 1 Checking Tire/Wheel/Hub Runout
1 - RADIAL RUNOUT
2 - LATERAL RUNOUT
Fig. 2 Radial Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
Fig. 3 Lateral Runout
1 - MOUNTING CONE
2 - SPINDLE SHAFT
3 - WING NUT
4 - PLASTIC CUP
5 - DIAL INDICATOR
6 - WHEEL
7 - DIAL INDICATOR
22 - 2 TIRES/WHEELSDR
TIRES/WHEELS (Continued)
For dynamic balancing, the balancing equipment is
designed to locate the amount of weight to be applied
to both the inner and outer rim flange (Fig. 10).
TIRES
DESCRIPTION
DESCRIPTION - SPARE TIRE / TEMPORARY
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
DESCRIPTION - TIRES
Tires are designed and engineered for each specific
vehicle. They provide the best overall performance
for normal operation. The ride and handling charac-
teristics match the vehicle's requirements. With
proper care they will give excellent reliability, trac-
tion, skid resistance, and tread life.
Driving habits have more effect on tire life than
any other factor. Careful drivers will obtain in most
cases, much greater mileage than severe use or care-
less drivers. A few of the driving habits which will
shorten the life of any tire are:
²Rapid acceleration
²Severe brake applications²High speed driving
²Excessive speeds on turns
²Striking curbs and other obstacles
Radial-ply tires are more prone to irregular tread
wear. It is important to follow the tire rotation inter-
val shown in the section on Tire Rotation, (Refer to
22 - TIRES/WHEELS - STANDARD PROCEDURE).
This will help to achieve a greater tread life.
TIRE IDENTIFICATION
Tire type, size, aspect ratio and speed rating are
encoded in the letters and numbers imprinted on the
side wall of the tire. Refer to the chart to decipher
the tire identification code (Fig. 11).
Performance tires have a speed rating letter after
the aspect ratio number. The speed rating is not
always printed on the tire sidewall. These ratings
are:
²Qup to 100 mph
²Rup to 106 mph
²Sup to 112 mph
²Tup to 118 mph
²Uup to 124 mph
²Hup to 130 mph
²Vup to 149 mph
²Zmore than 149 mph (consult the tire manu-
facturer for the specific speed rating)
An All Season type tire will have eitherM+S,M
&SorM±S(indicating mud and snow traction)
imprinted on the side wall.
Fig. 10 Dynamic Unbalance & Balance
1 - CENTER LINE OF SPINDLE
2 - ADD BALANCE WEIGHTS HERE3 - CORRECTIVE WEIGHT LOCATION
4 - HEAVY SPOT WHEEL SHIMMY AND VIBRATION
DRTIRES/WHEELS 22 - 5
TIRES/WHEELS (Continued)
TIRE CHAINS
Tire snow chains may be used oncertainmodels.
Refer to the Owner's Manual for more information.
DESCRIPTION - RADIAL ± PLY TIRES
Radial-ply tires improve handling, tread life and
ride quality, and decrease rolling resistance.
Radial-ply tires must always be used in sets of
four. Under no circumstances should they be used on
the front only. They may be mixed with temporary
spare tires when necessary. A maximum speed of 50
MPH is recommended while a temporary spare is in
use.
Radial-ply tires have the same load-carrying capac-
ity as other types of tires of the same size. They also
use the same recommended inflation pressures.
The use of oversized tires, either in the front or
rear of the vehicle, can cause vehicle drive train fail-
ure. This could also cause inaccurate wheel speed
signals when the vehicle is equipped with Anti-Lock
Brakes.
The use of tires from different manufactures on the
same vehicle is NOT recommended. The proper tire
pressure should be maintained on all four tires.
DESCRIPTION - TIRE PRESSURE FOR HIGH
SPEEDS
Where speed limits allow the vehicle to be driven at
high speeds, correct tire inflation pressure is very
important. For speeds up to and including 120 km/h (75
mph), tires must be inflated to the pressures shown on
the tire placard. For continuous speeds in excess of 120
km/h (75 mph), tires must be inflated to the maximum
pressure specified on the tire sidewall.
Vehicles loaded to the maximum capacity should not
be driven at continuous speeds above 75 mph (120
km/h).
For emergency vehicles that are driven at speeds
over 90 mph (144 km/h), special high speed tires
must be used. Consult tire manufacturer for correct
inflation pressure recommendations.
DESCRIPTION - REPLACEMENT TIRES
The original equipment tires provide a proper bal-
ance of many characteristics such as:
²Ride
²Noise
²Handling
²Durability
²Tread life
²Traction
²Rolling resistance
²Speed capability
It is recommended that tires equivalent to the orig-
inal equipment tires be used when replacement is
needed.
Failure to use equivalent replacement tires may
adversely affect the safety and handling of the vehicle.
The use of oversize tires may cause interference
with vehicle components. Under extremes of suspen-
sion and steering travel, interference with vehicle
components may cause tire damage.
WARNING: FAILURE TO EQUIP THE VEHICLE WITH
TIRES HAVING ADEQUATE SPEED CAPABILITY
CAN RESULT IN SUDDEN TIRE FAILURE.
DESCRIPTION - TIRE INFLATION PRESSURES
Under inflation will cause rapid shoulder wear, tire
flexing, and possible tire failure (Fig. 12).
Over inflation will cause rapid center wear and
loss of the tire's ability to cushion shocks (Fig. 13).
Improper inflation can cause:
²Uneven wear patterns
²Reduced tread life
²Reduced fuel economy
²Unsatisfactory ride
²Vehicle drift
For proper tire pressure specification refer to the Tire
Inflation Pressure Chart provided with the vehicles
Fig. 11 Tire Identification
22 - 6 TIRES/WHEELSDR
TIRES (Continued)
(4) Tug on the hub/cap wheel skin to ensure that
they are properly installed.
INSTALLATION - FRONT
(1) Align the valve stem with the notch in the
wheel skin.
(2) Seat on side of the wheel skin's wire retainer
on to the wheel.
(3) Using a rubber mallet, strike the opposite side
of the wheel skin until the skin is properly seated.
NOTE: The wheel skin and the hub cap are fully
seated when there is a consistant gap between the
skin/ cap and the wheel.
(4) Tug on the hub cap/wheel skin to ensure that
they are properly installed.
SPARE TIRE
DESCRIPTION
DESCRIPTION - SPARE / TEMPORARY TIRE
The temporary spare tire is designed for emer-
gency use only. The original tire should be repaired
or replaced at the first opportunity, then reinstalled.
Do not exceed speeds of 50 M.P.H. when using the
temporary spare tire. Refer to Owner's Manual for
complete details.
DESCRIPTION - FULL SIZE, SPARE WHEEL
WITH MATCHING TIRE
The spare is a full usage wheel with a matching
tire, It can be used within the (posted legal) speed
limits or distance limitations as of the rest of the
vehicles four tires. Refer to Owner's Manual for com-
plete details.
DRTIRES/WHEELS 22 - 15
WHEEL COVER (Continued)