Tie DODGE RAM 1500 1998 2.G Owners Manual

SHIFT MECHANISM
DESCRIPTION
The gear shift mechanism provides six shift posi-
tions which are:
²PARK (P)
²REVERSE (R)
²NEUTRAL (N)
²DRIVE (D)
²Manual SECOND (2)
²Manual LOW (1)
OPERATION
Manual LOW (1) range provides first gear only.
Overrun braking is also provided in this range. Man-
ual SECOND (2) range provides first and second gear
only.
DRIVE range provides first, second, third, and
overdrive fourth gear ranges. The shift into overdrive
fourth gear range occurs only after the transmission
has completed the shift into D third gear range. No
further movement of the shift mechanism is required
to complete the 3-4 shift.
The fourth gear upshift occurs automatically when
the overdrive selector switch is in the ON position.
No upshift to fourth gear will occur if any of the fol-
lowing are true:
²The transmission fluid temperature is below 10É
C (50É F) or above 121É C (250É F).
²The shift to third is not yet complete.
²Vehicle speed is too low for the 3-4 shift to occur.
²Battery temperature is below -5É C (23É F).
SOLENOID
DESCRIPTION
The typical electrical solenoid used in automotive
applications is a linear actuator. It is a device that
produces motion in a straight line. This straight line
motion can be either forward or backward in direc-
tion, and short or long distance.
A solenoid is an electromechanical device that uses
a magnetic force to perform work. It consists of a coil
of wire, wrapped around a magnetic core made from
steel or iron, and a spring loaded, movable plunger,
which performs the work, or straight line motion.
The solenoids used in transmission applications
are attached to valves which can be classified asnor-
mally openornormally closed. Thenormally
opensolenoid valve is defined as a valve which
allows hydraulic flow when no current or voltage is
applied to the solenoid. Thenormally closedsole-
noid valve is defined as a valve which does not allow
hydraulic flow when no current or voltage is applied
to the solenoid. These valves perform hydraulic con-trol functions for the transmission and must there-
fore be durable and tolerant of dirt particles. For
these reasons, the valves have hardened steel pop-
pets and ball valves. The solenoids operate the valves
directly, which means that the solenoids must have
very high outputs to close the valves against the siz-
able flow areas and line pressures found in current
transmissions. Fast response time is also necessary
to ensure accurate control of the transmission.
The strength of the magnetic field is the primary
force that determines the speed of operation in a par-
ticular solenoid design. A stronger magnetic field will
cause the plunger to move at a greater speed than a
weaker one. There are basically two ways to increase
the force of the magnetic field:
1. Increase the amount of current applied to the
coil or
2. Increase the number of turns of wire in the coil.
The most common practice is to increase the num-
ber of turns by using thin wire that can completely
fill the available space within the solenoid housing.
The strength of the spring and the length of the
plunger also contribute to the response speed possi-
ble by a particular solenoid design.
A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
21 - 252 AUTOMATIC TRANSMISSION - 48REDR

A solenoid can also be described by the method by
which it is controlled. Some of the possibilities
include variable force, pulse-width modulated, con-
stant ON, or duty cycle. The variable force and pulse-
width modulated versions utilize similar methods to
control the current flow through the solenoid to posi-
tion the solenoid plunger at a desired position some-
where between full ON and full OFF. The constant
ON and duty cycled versions control the voltage
across the solenoid to allow either full flow or no flow
through the solenoid's valve.
OPERATION
When an electrical current is applied to the sole-
noid coil, a magnetic field is created which produces
an attraction to the plunger, causing the plunger to
move and work against the spring pressure and the
load applied by the fluid the valve is controlling. The
plunger is normally directly attached to the valve
which it is to operate. When the current is removed
from the coil, the attraction is removed and the
plunger will return to its original position due to
spring pressure.
The plunger is made of a conductive material and
accomplishes this movement by providing a path for
the magnetic field to flow. By keeping the air gap
between the plunger and the coil to the minimum
necessary to allow free movement of the plunger, the
magnetic field is maximized.
TORQUE CONVERTER
DESCRIPTION
The torque converter (Fig. 117) is a hydraulic
device that couples the engine crankshaft to the
transmission. The torque converter consists of an
outer shell with an internal turbine, a stator, anoverrunning clutch, an impeller and an electronically
applied converter clutch. The converter clutch pro-
vides reduced engine speed and greater fuel economy
when engaged. Clutch engagement also provides
reduced transmission fluid temperatures. The torque
converter hub drives the transmission oil (fluid)
pump and contains an o-ring seal to better control oil
flow.
The torque converter is a sealed, welded unit that
is not repairable and is serviced as an assembly.
CAUTION: The torque converter must be replaced if
a transmission failure resulted in large amounts of
metal or fiber contamination in the fluid.
Fig. 117 Torque Converter Assembly
1 - TURBINE ASSEMBLY
2-STATOR
3 - CONVERTER HUB
4 - O-RING
5 - IMPELLER ASSEMBLY
6 - CONVERTER CLUTCH PISTON
7 - TURBINE HUB
DRAUTOMATIC TRANSMISSION - 45RFE/545RFE 21 - 399
SOLENOIDS (Continued)

SPECIFICATIONS - TORQUE
TORQUE SPECIFICATIONS
Description N´m Ft. Lbs. In. Lbs.
A-pillar trim/grab handle bolts 6 Ð 55
Body Isolator/cab bolts 81 60 Ð
Cargo box bolts 108 80 Ð
Cargo box tie down/cleat bolts 34 25 Ð
Center seat assembly nuts*25 18 Ð
Center seat cushion/hinge bolts*20 15 Ð
Center seat back hinge to storage bin bolts*25 18 Ð
Center seat back free pivot hinge bolt*25 18 Ð
Center seat back inertia hinge pivot bolt*10 Ð 89
Center seat inertia hinge to seat back bolts*25 18 Ð
Fender bolts - front lower 9 Ð 80
Fender bolts - lower inside 17 13 Ð
Fender to hinge support bolts 11 8 Ð
Fender to upper fender rail bolts 9 Ð 80
Footmans loop bolts 12 9 Ð
Front center seat nuts*25 18 Ð
Front door glass lift plate nuts 10 Ð 89
Front door hinge to a-pillar nuts 28 21 Ð
Front door hinge to door nuts/bolts 28 21 Ð
Front door inside handle bolt 9 Ð 80
Front door latch adjustment screw 3 Ð 30
Front door latch assembly bolts 10 Ð 89
Front door latch striker bolts 28 21 Ð
Front door latch striker bolts 28 21 Ð
Front door regulator bolts 10 Ð 89
Front door regulator stabilizer nuts 10 Ð 89
Front door remote handle actuator nuts 10 Ð 89
Front door run channel screws 10 Ð 89
Front seat assembly front bolts*28 30 Ð
Front seat assembly rear bolts*40 30 Ð
Front seat track nuts*25 18 Ð
Fuel fill door bolts 9 Ð 80
Hood hinge to fender rail bolts 20 15 Ð
Hood latch bolts 11 8 Ð
Hood latch striker/safety catch bolts 11 8 Ð
Hood hinge to hood nuts 23 17 Ð
Instrument panel center bracket bolts 12 9 Ð
Instrument panel column support bolts 14 10 Ð
Instrument panel side mounting bolts 12 9 Ð
23 - 12 BODYDR
BODY (Continued)

EXTERIOR
TABLE OF CONTENTS
page page
BODY SIDE MOLDINGS
REMOVAL.............................36
INSTALLATION.........................36
BODY ISOLATORS
REMOVAL.............................36
INSTALLATION.........................37
CARGO BOX
REMOVAL.............................37
INSTALLATION.........................37
CARGO BOX - TIE DOWN
REMOVAL.............................38
INSTALLATION.........................38
COWL GRILLE
REMOVAL.............................38
INSTALLATION.........................38
EXTERIOR NAME PLATES
REMOVAL.............................38
INSTALLATION.........................38
FRONT FENDER
REMOVAL.............................39
INSTALLATION.........................39
FUEL FILL DOOR
REMOVAL.............................39
INSTALLATION.........................39GRILLE
REMOVAL.............................40
INSTALLATION.........................40
GRILLE FRAME
REMOVAL.............................40
INSTALLATION.........................40
FRONT WHEELHOUSE SPLASH SHIELD
REMOVAL.............................41
INSTALLATION.........................41
REAR WHEELHOUSE SPLASH SHIELD
REMOVAL.............................41
INSTALLATION.........................41
SIDE VIEW MIRROR
REMOVAL.............................41
INSTALLATION.........................42
UPPER RADIATOR CROSSMEMBER
REMOVAL.............................42
INSTALLATION.........................42
SIDE VIEW MIRROR GLASS
REMOVAL.............................42
INSTALLATION.........................43
REAR FENDER
REMOVAL.............................44
INSTALLATION.........................44
BODY SIDE MOLDINGS
REMOVAL
NOTE: Body side moldings are attached to the body
panels with adhesive tape.
(1) Apply a length of masking tape on the body
panel, parallel to the top edge of the molding and to
one end to use as a guide for installation, if neces-
sary.
(2) If temperature is below 21ÉC (70ÉF) warm
molding with a heat lamp or gun. Do not exceed 52ÉC
(120ÉF) when heating molding.
(3) Using a trim stick C-4755 or equivalent,
remove and discard the molding from the outside of
the body panel.
INSTALLATION
(1) Thoroughly clean all residue from the body side
molding attachment area of the body panel.(2) Wipe area with a clean lint free cloth moist-
ened with a 50% solution of water and alcohol and
wipe dry immediately with a dry lint free cloth.
(3) Apply new body side molding using the guide
tape on the body panel and apply consistent and uni-
form pressure of approximately 40 p.s.i. over the
entire surface of the molding.
BODY ISOLATORS
REMOVAL
(1) Loosen all cab to frame mounting bolts (six
standard cab, eight quad cab). (Fig. 1)
(2) Remove the mounting bolts and rebound cush-
ions
(3) Using a floor jack and block of wood under the
cab sill, lift the body to gain access to the isolators.
(4) Remove the isolators.
(5) Install new isolators and repeat steps one
through 4, for the opposite side.
23 - 36 EXTERIORDR

CARGO BOX - TIE DOWN
REMOVAL
(1) Remove the bolts and remove the tie down
cleat. (Fig. 4)
INSTALLATION
(1) Install the tie down cleat and install the bolts.
(2) Tighten the bolts to 34 N´m (25 ft. lbs.).
COWL GRILLE
REMOVAL
(1) Remove the wiper arms. (Refer to 8 - ELEC-
TRICAL/WIPERS/WASHERS/WIPER ARMS -
REMOVAL)
(2) Disconnect the washer hose.
(3) Remove the hood seal.
(4) Remove the six push pin fasteners from the
front of the grille. (Fig. 5)
(5) Remove the two rear corner screws and remove
the grilles.
INSTALLATION
(1) Install the grill and install the two rear corner
screws.
(2) Install the six push pin fasteners along the
front of the grille.
(3) Install the hood seal.
(4) Connect the washer hose.(5) Install the wiper arms. (Refer to 8 - ELECTRI-
CAL/WIPERS/WASHERS/WIPER ARMS - INSTAL-
LATION)
EXTERIOR NAME PLATES
REMOVAL
NOTE: Exterior name plates are attached to body
panels with adhesive tape.
(1) Apply a length of masking tape on the body,
parallel to the top edge and one end of the name
plate to use as a guide for installation, if necessary.
(2) If temperature is below 21ÉC (70ÉF) warm
emblem with a heat lamp or gun. Do not exceed 52ÉC
(120ÉF) when heating name plate.
(3) Using a trim stick C-4755 or equivalent,
remove and discard the name plate.
INSTALLATION
(1) Thoroughly clean all residue from the name
plate attachment area of the body panel.
(2) Wipe area with a clean lint free cloth moist-
ened with a 50% solution of water and alcohol and
wipe dry immediately with a dry lint free cloth.
(3) Remove protective cover from adhesive tape on
back of name plate.
(4)
Position name plate properly on the body panel.
(5) Apply consistent and uniform pressure over the
entire surface of the name plate, with palm of hand.
(6) If temperature is below 21ÉC (70ÉF) warm
emblem with a heat lamp or gun to assure adhesion.
Do not exceed 52ÉC (120ÉF) when heating name
plate.
Fig. 4 TIE DOWN CLEAT
1 - BOLTS (2)
2 - CLEAT
Fig. 5 COWL GRILLE
1 - PUSH PIN FASTENERS (6)
2 - COWL GRILLE
3 - SCREWS (2)
23 - 38 EXTERIORDR

DESCRIPTION FIGURE
REAR ROOF HEADER TO OUTER ROOF PANEL TO INNER BODY SIDE APERTURE
TO OUTER BODY SIDE APERTURE81
OUTER BODY SIDE APERTURE TO CAB BACK PANEL TO FLOOR SILL, INNER BODY
SIDE APERTURE TO FLOOR SILL82
OUTER BODY SIDE APERTURE TO INNER BODY SIDE APERTURE TO FLOOR SILL 83
REAR FLOOR CROSSMEMBER AND CAB BACK REINFORCEMENT TO CAB BACK
PANEL TO INNER BODY SIDE APERTURE84
CAB BACK REINFORCEMENT TO CAB BACK PANEL 85
CENTER SHOULDER BELT REINFORCEMENT AND TAPPING PLATES TO CAB BACK
REINFORCEMENT86
A-PILLAR REINFORCEMENT TO COWL SIDE PANEL TO OUTER BODY SIDE
APERTURE/APERTURE EXTENSION TO COWL SIDE PANEL87
B-PILLAR REINFORCEMENT TO OUTER ROOF PANEL TO OUTER BODY SIDE
APERTURE88
FRONT ROOF HEADER TO OUTER ROOF PANEL/ROOF BOW TO INNER BODY SIDE
APERTURE/FRONT ROOF HEADER TO A-PILLAR REINFORCEMENT89
INNER BODY SIDE APERTURE TO REAR ROOF HEADER AND OUTER BODY SIDE
APERTURE TO OUTER ROOF PANEL90
FRONT CROSSMEMBER, WHEELHOUSE CROSSMEMBER AND BRACKET SUPPORT
CROSSMEMBER TO BOX FLOOR PAN91
LONG CROSSMEMBER AND FLOOR BOX CROSS SILL TO BOX FLOOR PAN 92
TAPPING PLATES AND SUPPORT BRACKETS TO REAR CROSS BOX SILL, FRONT
WHEELHOUSE, LONG AND BRACKET SUPPORT CROSSMEMBERS93
STAKE POCKET REINFORCEMENTS AND TIE DOWN REINFORCEMENTS TO INNER
BOX SIDE PANEL94
OUTER BOX SIDE REINFORCEMENT BRACES NUT PLATES TO OUTER BOX SIDE
PANEL MOUNTING95
OUTER WHEELHOUSE TO OUTER BOX SIDE PANEL 96
WELD NUT STRIKER CAGE NUT, OUTER BOX SIDE PANEL AND NUT PLATE TO BOX
SIDE TAILGATE REINFORCEMENT97
FRONT BOX PANEL TO FRONT INNER STAKE POCKET REINFORCEMENT TO FRONT
BOX SIDE PANEL98
FRONT CROSSMEMBER TO FRONT BOX SIDE PANEL AND BOX FLOOR PANEL TO
BOX FRONT PANEL99
BOX FLOOR PANEL AND INNER WHEELHOUSE PANEL TO INNER BOX SIDE PANEL 100
FRONT CROSSMEMBER AND END SUPPORT BRACKET TO LONG CROSSMEMBER
TO INNER BOX SIDE PANEL/STAKE POCKET REINFORCEMENT AND BOX FLOOR
SILL TO OUTER TAILGATE PILLAR TO INNER TAILGATE PILLAR101
STAKE POCKET REINFORCEMENT AND BOX FLOOR SILL CROSSMEMBER TO
INNER TAILGATE PILLAR102
INNER TAILGATE PILLAR PANEL TO INNER BOX SIDE PANEL TO TIE DOWN
MOUNTING REINFORCEMENT103
BOX FLOOR SILL CROSSMEMBER TO INNER BOX SIDE PANEL 104
INNER TAILGATE PILLAR TO TAILGATE BOX SIDE REINFORCEMENT TO OUTER
TAILGATE PILLAR105
BOX SIDE PANEL AND OUTER TAILGATE PILLAR TO OUTER BOX SIDE PANEL 106
FRONT BOX PANEL TO OUTER BOX SIDE PANEL 107
23 - 122 BODY STRUCTUREDR
WELD LOCATIONS (Continued)

DESCRIPTION FIGURE
INNER BOX SIDE PANEL AND INNER TAILGATE PILLAR TO OUTER BOX SIDE PANEL 108
OUTER WHEELHOUSE PANEL TO INNER WHEELHOUSE PANEL 109
FRONT CROSSMEMBER, LONG CROSSMEMBER, AND WHEELHOUSE
CROSSMEMBER TO FLOOR PAN11 0
WHEELHOUSE CROSSMEMBER, LONG CROSSMEMBER AND REAR CROSS BOX
SILL TO BOX FLOOR PAN111
FRONT AND CENTER STAKE POCKET REINFORCEMENTS AND TIE DOWN
MOUNTING REINFORCEMENT TO INNER BOX SIDE PANEL11 2
OUTER FRONT AND CENTER STAKE POCKET REINFORCEMENT AND OUTER TIE
DOWN MOUNTING REINFORCEMENT TO INNER BOX SIDE PANEL11 3
OUTER WHEELHOUSE AND OUTER BRACE MOUNTING REINFORCEMENT TO
OUTER BOX SIDE PANEL11 4
TAILGATE BOX SIDE PIVOT REINFORCEMENT TO OUTER BOX SIDE PANEL 115
FRONT BOX SIDE PANEL TO FRONT CROSSMEMBER TO INNER BOX SIDE PANEL 116
FRONT BOX SIDE PANEL TO BOX FRONT PANEL TO INNER BOX SIDE PANEL/
FRONT STAKE POCKET REINFORCEMENT TO FRONT BOX SIDE PANEL TO BOX
FRONT PANEL11 7
BOX FRONT PANEL TO BOX FLOOR PANEL 118
BOX FLOOR PANEL TO INNER BOX SIDE PANEL 119
LONG CROSSMEMBERS TO CROSSMEMBER END SUPPORT BRACKETS TO INNER
BOX SIDE PANEL120
INNER WHEELHOUSE PANEL TO INNER BOX SIDE PANEL 121
TAILGATE PILLAR OUTER PANEL TO TAILGATE PILLAR INNER PANEL TO INNER
BOX SIDE PANEL122
REAR SILL CROSS BOX TO TAILGATE PILLAR OUTER PANEL AND INNER BOX SIDE
PANEL123
OUTER BOX SIDE PANEL TO BOX FRONT PANEL AND BOX FRONT SIDE PANEL 124
STAKE POCKET REINFORCEMENTS TO INNER BOX SIDE PANEL TO OUTER BOX
SIDE PANEL125
TAILGATE PIVOT REINFORCEMENT AND INNER TAILGATE PILLAR TO INNER BOX
SIDE PANEL TO OUTER BOX SIDE PANEL126
INNER WHEELHOUSE TO OUTER WHEELHOUSE/TAILGATE PIVOT
REINFORCEMENT TO OUTER TAILGATE PILLAR TO INNER TAILGATE PILLAR127
OUTER TAILGATE PILLAR TO OUTER BOX SIDE PANEL 128
INNER DOOR PANEL TO OUTER DOOR PANEL - FRONT DOOR (QUAD CAB) 129
INNER DOOR PANEL TO OUTER DOOR PANEL - FRONT DOOR (STANDARD CAB) 130
INNER DOOR PANEL TO OUTER DOOR PANEL - REAR DOOR (QUAD CAB) 131
DRBODY STRUCTURE 23 - 123
WELD LOCATIONS (Continued)

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - ENGINE COOLING
SYSTEM REQUIREMENTS...............1
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
OPERATION - HEATER AND AIR
CONDITIONER........................1
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................3DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST..................6
SPECIFICATIONS - A/C SYSTEM............7
CONTROLS.............................9
DISTRIBUTION..........................26
PLUMBING.............................41
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - ENGINE COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the heating,
ventilation and air conditioning (HVAC) system, the
engine cooling system must be properly maintained.
The use of a bug screen is not recommended. Any
obstructions in front of the radiator or A/C condenser
will reduce the performance of the A/C and engine
cooling systems.
The engine cooling system includes the radiator,
thermostat, radiator hoses and the engine coolant
pump. Refer to Cooling for more information before
opening or attempting any service to the engine cool-
ing system.
DESCRIPTION - HEATER AND AIR
CONDITIONER
A manually controlled single zone type heating-air
conditioning system or a manually controlled dual
zone type heating-air conditioning system is available
on this model.
All vehicles are equipped with a common heater,
ventilation and air conditioning (HVAC) housing (Fig.
1). The system combines air conditioning, heating,
and ventilating capabilities in a single unit housing
mounted within the passenger compartment under
the instrument panel. The HVAC housing includes:
²Blower motor
²Blower motor resistor block²Heater core
²Evaporator coil
²Blend door and actuator
²Defrost door and actuator
²Mode door and actuator
²Recirculation door and actuator
Based upon the system and mode selected, condi-
tioned air can exit the HVAC housing through one or
a combination of the three main housing outlets:
defrost, panel or floor. The defrost outlet is located on
the top of the housing, the panel outlet is located on
the face of the housing and the floor outlet is located
on the bottom of the housing. Once the conditioned
air exits the unit housing, it is further directed
through molded plastic ducts to the various outlets in
the vehicle interior. These outlets and their locations
are as follows:
²Defroster Outlet- A single large defroster out-
let is located in the center of the instrument panel
top cover, near the base of the windshield.
²Side Window Demister Outlets- There are
two side window demister outlets, one is located at
each outboard end of the instrument panel top cover,
near the belt line at the A-pillars.
²Panel Outlets- There are four panel outlets in
the instrument panel, one located near each outboard
end of the instrument panel facing the rear of the
vehicle and two located near the top of the instru-
ment panel center bezel.
²Front Floor Outlets- There are two front floor
outlets, one located above each side of the floor panel
center tunnel near the dash panel.
OPERATION - HEATER AND AIR CONDITIONER
The heating and air conditioning systems pulls
outside (ambient) air through the cowl opening at the
base of the windshield, then into the plenum cham-
DRHEATING & AIR CONDITIONING 24 - 1

NOTE: The air gap is determined by the spacer
shims. When installing an original, or a new clutch
assembly, try the original shims first. When install-
ing a new clutch onto a compressor that previously
did not have a clutch, use a 1.0, 0.50, and 0.13 mil-
limeter (0.040, 0.020, and 0.005 inch) shims from the
new clutch hardware package that is provided with
the new clutch.
(9) To complete the procedure (Refer to 24 - HEAT-
ING & AIR CONDITIONING/PLUMBING/A/C COM-
PRESSOR - INSTALLATION).
A/C COMPRESSOR CLUTCH
RELAY
DESCRIPTION
The A/C compressor clutch relay (Fig. 10) is a
International Standards Organization (ISO) micro-re-
lay. 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 A/C compressor clutch relay is located in the
intergrated power module (IPM) in the engine com-
partment. See the fuse and relay layout label affixed
to the inside surface of the IPM cover for A/C com-
pressor clutch relay identification and location.
The black, molded plastic case is the most visible
component of the A/C compressor clutch relay. Fivemale spade-type terminals extend from the bottom of
the base to connect the relay to the vehicle electrical
system, 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.
OPERATION
The A/C compressor clutch relay is an electrome-
chanical switch that uses a low current input from
the powertrain control module (PCM) or engine con-
trol module (ECM) depending on engine application,
to control the high current output to the compressor
clutch electromagnetic 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 windings. 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
Fig. 9 Check Clutch Air Gap - Typical
1 - FEELER GAUGE
Fig. 10 A/C Compressor Clutch Micro-Relay
30 - COMMON FEED
85 - COIL GROUND
86 - COIL BATTERY
87 - NORMALLY OPEN
87A - NORMALLY CLOSED
DRCONTROLS 24 - 13
A/C COMPRESSOR CLUTCH/COIL (Continued)

spikes and electromagnetic interference that can be
generated as the electromagnetic field of the relay
coil collapses.
The A/C compressor clutch relay terminals are con-
nected to the vehicle electrical system through a
receptacle in the integrated power module (IPM). The
inputs and outputs of the A/C 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 (86) receives a ground
input from the PCM/ECM through the A/C compres-
sor clutch relay control circuit only when the PCM/
ECM electronically pulls the control circuit to
ground.
²The coil battery terminal (85) receives a battery
current input from PTC 1 in the IPM through a
fused ignition switch output (run) circuit only when
the ignition switch is in the On position.
²The normally open terminal (87) provides a bat-
tery current output to the compressor clutch coil
through the A/C compressor clutch relay output cir-
cuit only when the A/C compressor clutch relay coil is
energized.
²The normally closed terminal (87A) is not con-
nected to any circuit in this application, but provides
a battery current output only when the A/C compres-
sor clutch relay coil is de-energized.
Refer to the appropriate wiring information for
diagnosis and testing of the micro-relay and for com-
plete HVAC wiring diagrams.
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Remove the cover from the integrated power
module (IPM) (Fig. 11).
(3) Refer to the fuse and relay layout label on the
IPM cover for compressor clutch relay identification
and location.
(4) Remove the A/C compressor clutch relay from
the IPM.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the IPM cover for A/C compressor
clutch relay location.
(2) Position the A/C compressor clutch relay in the
proper receptacle in the IPM.
(3) Align the A/C compressor clutch relay termi-
nals with the terminal cavities in the IPM receptacle.
(4) Push down firmly on the A/C compressor clutch
relay until the terminals are fully seated in the ter-
minal cavities in the IPM receptacle.
(5) Install the cover onto the IPM.(6) Reconnect the negative battery cable.
A/C HEATER CONTROL
DESCRIPTION
The heater and air conditioning systems use elec-
trical controls. These controls provide the vehicle
operator with a number of setting options to help
control the climate and comfort within the vehicle.
The A/C-heater control for the Single Zone system
(Fig. 12) or Dual Zone system (Fig. 13) is located to
the right of the instrument cluster on the instrument
panel.
The Single Zone control panel contains a rotary-
type temperature control switch, a rotary-type mode
control switch and a rotary-type blower motor speed
switch. The A/C-heater control also has a push but-
ton to activate the optional heated side view mirror
defroster elements and to turn the A/C on.
The Dual Zone control panel contains a pair of slid-
er-type temperature control switches, a rotary-type
mode control switch and a rotary-type blower motor
speed switch. The control also has buttons to activate
the optional heated sideview mirror defroster ele-
ments, turn the A/C on and set the system to Max
A/C.
The A/C-heater control panel cannot be repaired. If
faulty or damaged, the entire unit must be replaced.
Fig. 11 Integrated Power Module (IPM)
1 - BATTERY
2 - INTEGRATED POWER MODULE (IPM)
24 - 14 CONTROLSDR
A/C COMPRESSOR CLUTCH RELAY (Continued)