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)
ProCarManuals.com
(5) Install and tighten the three screws that secure
the heater core shield to the left end of the heater/air
conditioner housing. Tighten the screws to 2 N´m (17
in. lbs.).
(6) Reinstall the silencer under the driver side end
of the instrument panel. (Refer to 23 - BODY/IN-
STRUMENT PANEL/INSTRUMENT PANEL
SILENCER - INSTALLATION).
(7) Reconnect the battery negative cable.
(8) Perform the heater-A/C control calibration pro-
cedure. (Refer to 24 - HEATING & AIR CONDITION-
ING/CONTROLS - FRONT/A/C-HEATER CONTROL
- STANDARD PROCEDURE - HEATER-A/C CON-
TROL CALIBRATION).
BLOWER MOTOR RELAY
DESCRIPTION
The blower motor relay (Fig. 6) is a International
Standards Organization (ISO) mini-relay. Relays con-
forming to the ISO specifications have common phys-
ical dimensions, current capacities, terminal
patterns, and terminal functions. The ISO mini-relay
terminal functions are the same as a conventional
ISO relay. However, the ISO mini-relay terminal pat-
tern (or footprint) is different, the current capacity is
lower, and the physical dimensions are smaller than
those of the conventional ISO relay. The blower
motor relay is located in the Intelligent Power Mod-
ule (IPM), which is in the engine compartment near
the battery. See the fuse and relay layout mapmolded into the inner surface of the IPM cover for
blower motor relay identification and location.
The black, molded plastic case is the most visible
component of the blower motor 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 blower motor relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control the high current
output to the blower motor resistor (manual heater-
A/C control) or blower power module (ATC control).
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 blower motor relay terminals are connected to
the vehicle electrical system through a receptacle in
the Intelligent Power Module (IPM). The inputs and
outputs of the blower motor relay include:
²The common feed terminal (30) receives a bat-
tery current input from the battery through a B(+)
circuit at all times.
²The coil ground terminal (85) receives a ground
input through the front/rear blower motor relay con-
trol circuit only when the FCM electronically pulls
the control circuit to ground.
²The coil battery terminal (86) receives a battery
current input from the battery through a B(+) circuit
at all times.
²The normally open terminal (87) provides a bat-
tery current output to the blower motor resistor
(manual heater-A/C control) or blower power module
(automatic heater-A/C control) through a fuse in the
IPM on the fused front blower motor relay output cir-
cuit only when the blower motor relay coil is ener-
gized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the blower motor
relay coil is de-energized.
Fig. 6 Blower Motor Relay
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
RSCONTROLS - FRONT24-13
BLEND DOOR ACTUATOR (Continued)
ProCarManuals.com
(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)
ProCarManuals.com
quarter inner panel. Tighten the screw to 11 N´m (97
in. lbs.).
(7) Install and tighten the screw that secures the
back of the rear heater-A/C unit housing to the right
D-pillar. Tighten the screw to 11 N´m (97 in. lbs.).
(8) Install and tighten the two screws that secure
the top of the quarter trim panel attaching bracket to
the quarter inner panel. Tighten the screws to 1.7
N´m (15 in. lbs.).
(9) Reinstall the right quarter trim panel and
right D-pillar trim panel onto the quarter inner
panel. (Refer to 23 - BODY/INTERIOR/QUARTER
TRIM PANEL - INSTALLATION).
(10) Reconnect the battery negative cable.
(11) Perform the heater-A/C control calibration
procedure. (Refer to 24 - HEATING & AIR CONDI-
TIONING/CONTROLS - FRONT/A/C-HEATER CON-
TROL - STANDARD PROCEDURE - HEATER-A/C
CONTROL CALIBRATION).
BLOWER MOTOR RELAY
DESCRIPTION
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
The blower motor relay (Fig. 5) is a International
Standards Organization (ISO) mini-relay. Relays con-
forming to the ISO specifications have common phys-
ical dimensions, current capacities, terminalpatterns, and terminal functions. The ISO mini-relay
terminal functions are the same as a conventional
ISO relay. However, the ISO mini-relay terminal pat-
tern (or footprint) is different, the current capacity is
lower, and the physical dimensions are smaller than
those of the conventional ISO relay. The blower
motor relay is located in the Intelligent Power Mod-
ule (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 blower motor 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. The
ISO terminal designations are as follows:
²30 (Common Feed)- This terminal is con-
nected to the movable contact point of the relay.
²85 (Coil Ground)- This terminal is connected
to the ground feed side of the relay control coil.
²86 (Coil Battery)- This terminal is connected
to the battery feed side of the relay control coil.
²87 (Normally Open)- This terminal is con-
nected to the normally open fixed contact point of the
relay.
²87A (Normally Closed)- This terminal is con-
nected to the normally closed fixed contact point of
the relay.
The factory-installed blower motor relay cannot be
adjusted or repaired. If the relay is damaged or
faulty, it must be replaced.
OPERATION
The blower motor relay is an electromechanical
switch that uses a low current input from the Front
Control Module (FCM) to control the high current
output to the blower motor resistor (manual heater-
A/C control) or blower power module (automatic heat-
er-A/C control). The movable common feed contact
point is held against the fixed normally closed con-
tact point by spring pressure. When the relay coil is
energized, an electromagnetic field is produced by the
coil windings. This electromagnetic field draws the
movable relay contact point away from the fixed nor-
mally closed contact point, and holds it against the
fixed normally open contact point. When the relay
coil is de-energized, spring pressure returns the mov-
able contact point back against the fixed normally
closed contact point. The resistor or diode is con-
nected in parallel with the relay coil in the relay, and
helps to dissipate voltage spikes and electromagnetic
interference that can be generated as the electromag-
netic field of the relay coil collapses.
Fig. 5 Blower Motor Relay
24 - 32 CONTROLS - REARRS
BLEND DOOR ACTUATOR (Continued)
ProCarManuals.com
STANDARD PROCEDURE - REFRIGERANT
RECOVERY
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
A R-134a refrigerant recovery/recycling/charging
station that meets SAE Standard J2210 must be
used to recover the refrigerant from an R-134a refrig-
erant system, whenever the refrigerant system must
be opened for service. See the operating instructions
supplied by the equipment manufacturer for the
proper care and use of this equipment.
REFRIGERANT OIL
DESCRIPTION
The refrigerant oil used in R-134a refrigerant sys-
tems is a synthetic-based, PolyAlkylene Glycol (PAG),
wax-free lubricant. Mineral-based R-12 refrigerant
oils are not compatible with PAG oils, and should
never be introduced to an R-134a refrigerant system.
There are different PAG oils available, and each con-
tains a different additive package. The 10S20H com-
pressor used in this vehicle are designed to use an
ND-8 PAG refrigerant oil. Use only refrigerant oil of
this same type to service the refrigerant system.
OPERATION
After performing any refrigerant recovery or recy-
cling operation, always replenish the refrigerant sys-
tem with the same amount of the recommended
refrigerant oil as was removed. Too little refrigerant
oil can cause compressor damage, and too much can
reduce air conditioning system performance. PAG
refrigerant oil is much more hygroscopic than min-
eral oil, and will absorb any moisture it comes into
contact with, even moisture in the air. The PAG oil
container should always be kept tightly capped until
it is ready to be used. After use, recap the oil con-
tainer immediately to prevent moisture contamina-
tion.
STANDARD PROCEDURE - REFRIGERANT OIL
LEVEL
WARNING: REFER TO THE APPLICABLE WARN-
INGS AND CAUTIONS FOR THIS SYSTEM BEFORE
PERFORMING THE FOLLOWING OPERATION.
(Refer to 24 - HEATING & AIR CONDITIONING/PLUMBING - FRONT - WARNING - A/C PLUMBING)
and (Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - FRONT - CAUTION - A/C PLUMBING).
When an air conditioning system is assembled at
the factory, all components except the compressor are
refrigerant oil free. After the refrigerant system has
been charged and operated, the refrigerant oil in the
compressor is dispersed throughout the refrigerant
system. The receiver/drier, evaporator, condenser, and
compressor will each retain a significant amount of
the needed refrigerant oil.
It is important to have the correct amount of oil in
the refrigerant system. This ensures proper lubrica-
tion of the compressor. Too little oil will result in
damage to the compressor. Too much oil will reduce
the cooling capacity of the air conditioning system.
It will not be necessary to check the oil level in the
compressor or to add oil, unless there has been an oil
loss. An oil loss may occur due to a rupture or leak
from a refrigerant line, a connector fitting, a compo-
nent, or a component seal. If a leak occurs, add 30
milliliters (1 fluid ounce) of refrigerant oil to the
refrigerant system after the repair has been made.
Refrigerant oil loss will be evident at the leak point
by the presence of a wet, shiny surface around the
leak.
Refrigerant oil must be added when an receiver/
drier, evaporator or condenser is replaced. See the
Refrigerant Oil Capacities chart for the proper
amount of refrigerant oil to add. When a compressor
is replaced, the refrigerant oil must be drained from
the old compressor and measured. Drain all of the
refrigerant oil from the new compressor, then fill the
new compressor with the same amount of fresh new
refrigerant oil that was drained out of the old com-
pressor.
REFRIGERANT OIL CAPACITIES
Front A/C Front & Rear
A/C
COMPONENT ml fl oz ml fl oz
Compressor 150 5.0 220 7.4
Filter-Drier 30 1.0 30 1.0
Condenser 30 1.0 30 1.0
Front Evaporator 60 2.0 60 2.0
Rear Evap. (including
underbody lines)N/A N/A 60 2.0
Compressor Drain and measure the oil
from the old compressor -
See text above.
RSPLUMBING - FRONT24-93
REFRIGERANT (Continued)
ProCarManuals.com