Over inflation causes rapid center wear and loss of
the tire's ability to cushion shocks (Fig. 26).
STANDARD PROCEDURE - TIRE PRESSURE
FOR HIGH SPEED OPERATION
DaimlerChrysler Corporation advocates driving at
safe speeds within posted speed limits. Where speed
limits allow the vehicle to be driven at high speeds,
correct tire inflation pressure is very important.
Vehicles loaded to maximum capacity should not be
driven at continuous speeds over 120 km/h (75 mph).
Never exceed the maximum speed capacity of the
tire. For information on tire identification and speed
ratings, (Refer to 22 - TIRES/WHEELS/TIRES -
DESCRIPTION).
STANDARD PROCEDURE - TIRE LEAK
REPAIRING
For proper repairing, a radial tire must be removed
from the wheel. Repairs should only be made if the
defect, or puncture, is in the tread area (Fig. 27). The
tire should be replaced if the puncture is located in
the sidewall.
Deflate tire completely before attempting to dis-
mount the tire from the wheel.Use a lubricant
such as a mild soap solution when dismounting
or mounting tire.Use tools free of burrs or sharp
edges which could damage the tire or wheel rim.
Before mounting tire on wheel, make sure all rust
is removed from the rim bead and repaint if neces-
sary.
Install wheel on vehicle, and progressively tighten
the 5 wheel nuts to a torque of 135 N´m (100 ft. lbs.).
CLEANING - TIRES
Before delivery of a vehicle, remove the protective
coating on the tires with white sidewalls or raisedwhite letters. To remove the protective coating, apply
warm water and let it soak for a few minutes. After-
wards, scrub the coating away with a soft bristle
brush. Steam cleaning may also be used to remove
the coating.
CAUTION: DO NOT use gasoline, mineral oil, oil-
based solvent or a wire brush for cleaning.
WHEELS
DESCRIPTION - WHEEL
Original equipment wheels are designed for proper
operation at all loads up to the specified maximum
vehicle capacity.
All models use either steel or aluminum drop-cen-
ter wheels. Every wheel has raised sections between
the rim flanges and rim drop well called safety
humps (Fig. 28). Initial inflation of the tires forces
the bead over these raised sections. In case of air
loss, the safety humps hold the tire in position on the
wheel until the vehicle can be brought to a safe stop.
Cast aluminum wheels require special balance
weights to fit on the flange of the rim (Fig. 29).
When wheel alignment is necessary on a vehicle
with cast aluminum wheels, special wheel clamps are
required to avoid damage to the wheel's finish.
The wheel studs and nuts are designed for specific
wheel applications and must be replaced with equiv-
alent parts.
Fig. 26 Over Inflation Wear
1 - THIN TIRE TREAD AREAFig. 27 Tire Repair Area
1 - REPAIRABLE AREA
RSTIRES/WHEELS22-17
TIRES (Continued)
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All aluminum wheels have wheel mounting (lug)
nuts with an enlarged nose. This enlarged nose is
necessary to ensure proper retention of the wheels.
DIAGNOSIS AND TESTING - WHEEL
INSPECTION
Inspect wheels for:
²Excessive runout
²Dents, cracks or irregular bends
²Damaged wheel stud (lug) holes
²Air Leaks
NOTE: Do not attempt to repair a wheel by hammer-
ing, heating or welding.
If a wheel is damaged, an original equipment
replacement wheel should be used. When obtaining
replacement wheels, they must be equivalent in load
carrying capacity. The diameter, width, offset, pilot
hole and bolt circle of the wheel should be the same
as the original wheel.
WARNING: FAILURE TO USE EQUIVALENT
REPLACEMENT WHEELS MAY ADVERSELY
AFFECT THE SAFETY AND HANDLING OF THE
VEHICLE.
WARNING: REPLACEMENT WITH USED WHEELS IS
NOT RECOMMENDED. THE SERVICE HISTORY OF
THE WHEEL MAY HAVE INCLUDED SEVERE TREAT-
MENT OR VERY HIGH MILEAGE. THE RIM COULD
FAIL WITHOUT WARNING.
CLEANING - ALUMINUM WHEEL CARE
Chrome plated and painted aluminum wheels
should be cleaned regularly using mild soap and
water to maintain their luster and to prevent corro-
sion.
Care must be taken in the selection of tire and
wheel cleaning chemicals and equipment to prevent
damage to the wheels. Any of the ªDO NOT USEº
items listed below WILL damage chrome plated and
painted aluminum wheels.
DO NOT USE:
²any abrasive metal cleaner
²any abrasive cleaning pad or brush
²any cleaner that contains an acid (this will
immediately react with and discolor the chromium
surface)
²chrome polish (unless it is buffed off immedi-
ately after application)
²oven cleaner
²a car wash that uses carbide-tipped wheel clean-
ing brushes
Fig. 28 Safety Rim
1 - TIRE
2 - WELL
3 - SAFETY HUMPS
4 - FLANGE
Fig. 29 Styled Aluminum Wheel Weight
1 - TIRE
2 - WHEEL
3 - STYLED WHEEL WEIGHT
22 - 18 TIRES/WHEELSRS
WHEELS (Continued)
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(2) If the a/c compressor clutch still will not
engage, disconnect the headlamp and dash wire har-
ness connector for the A/C pressure transducer and
check for battery current at the connector with the
engine running and the heater-A/C control set to the
A/C mode. If OK, go to TESTS . If not OK, use a
DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information.
TESTS
(1) Verify the battery state of charge. (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM/BATTERY -
DIAGNOSIS AND TESTING).
(2) Connect an ammeter (0 to 10 ampere scale
selected) in series with the clutch coil feed terminal.
Connect a voltmeter (0 to 20 volt scale selected) to
measure voltage across the battery and the clutch
coil.
(3) With the heater-A/C control in the A/C mode
and the blower at low speed, start the engine and
allow it to run at a normal idle speed.
(4) The compressor clutch should engage immedi-
ately, and the clutch coil voltage should be within
two volts of the battery voltage. If the coil voltage is
not within two volts of battery voltage, test the
clutch coil feed circuit for excessive voltage drop. If
the compressor clutch does not engage, use a
DRBIIItscan tool to perform further diagnosis. Refer
to the appropriate diagnostic information.
(5) With the ambient temperature at 21É C (70É F),
the compressor clutch coil is acceptable if the current
draw is 2.0 to 3.7 amperes at 11.5 to 12.5 volts at the
clutch coil. If the voltage is more than 12.5 volts, add
electrical loads by turning on electrical accessories
until the voltage reads below 12.5 volts.
(a) If the compressor clutch coil current reading
is zero, the coil is open and must be replaced.
(b) If the compressor clutch coil current reading
is four amperes or more, the coil is shorted and
must be replaced.
COMPRESSOR CLUTCH RELAY
DESCRIPTION
The compressor clutch relay (Fig. 17) is a Interna-
tional Standards Organization (ISO) micro-relay.
Relays conforming to the ISO specifications have
common physical dimensions, current capacities, ter-
minal patterns, and terminal functions. The ISO
micro-relay terminal functions are the same as a con-
ventional ISO relay. However, the ISO micro-relay
terminal pattern (or footprint) is different, the cur-
rent capacity is lower, and the physical dimensions
are smaller than those of the conventional ISO relay.
The compressor clutch relay is located in the Intelli-gent Power Module (IPM), which is in the engine
compartment near the battery. See the fuse and relay
layout map molded into the inner surface of the IPM
cover for compressor clutch relay identification and
location.
The black, molded plastic case is the most visible
component of the compressor clutch relay. Five male
spade-type terminals extend from the bottom of the
base to connect the relay to the vehicle electrical sys-
tem, and the ISO designation for each terminal is
molded into the base adjacent to each terminal.
OPERATION
The compressor clutch relay is an electromechani-
cal switch that uses a low current input from the
Powertrain Control Module (PCM) to control the high
current output to the compressor clutch electromag-
netic coil. The movable common feed contact point is
held against the fixed normally closed contact point
by spring pressure. When the relay coil is energized,
an electromagnetic field is produced by the coil wind-
ings. This electromagnetic field draws the movable
relay contact point away from the fixed normally
closed contact point, and holds it against the fixed
normally open contact point. When the relay coil is
de-energized, spring pressure returns the movable
contact point back against the fixed normally closed
contact point. The resistor or diode is connected in
parallel with the relay coil in the relay, and helps to
dissipate voltage spikes and electromagnetic interfer-
ence that can be generated as the electromagnetic
field of the relay coil collapses.
The compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the Intelligent Power Module (IPM).
The inputs and outputs of the compressor clutch
relay include:
²The common feed terminal (30) receives a bat-
tery current input from a fuse in the IPM through a
fused B(+) circuit at all times.
²The coil ground terminal (85) receives a ground
input from the PCM through the compressor clutch
relay control circuit only when the PCM electroni-
cally pulls the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the PCM through a fused ignition
switch output (run-start) circuit only when the igni-
tion switch is in the On or Start positions.
²The normally open terminal (87) provides a bat-
tery current output to the compressor clutch coil
through the compressor clutch relay output circuit
only when the compressor clutch relay coil is ener-
gized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
RSCONTROLS - FRONT24-21
COMPRESSOR CLUTCH COIL (Continued)
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