radiator DODGE RAM 2003 Service Repair Manual

(12) Carefully work transmission forward and over
engine block dowels until converter hub is seated in
crankshaft.
(13) Install bolts attaching converter housing to
engine.
(14) Install rear support.
(15) Install the rear transmission crossmember.
(16) Lower transmission onto crossmember and
install bolts attaching transmission mount to cross-
member.
(17) Remove engine support fixture.
(18) Install the transfer case, if equipped.
(19) Install crankshaft position sensor. (Refer to 14
- FUEL SYSTEM/FUEL INJECTION/CRANKSHAFT
POSITION SENSOR - INSTALLATION)
(20) Connect gearshift cable (Fig. 66) and throttle
cable to transmission.
(21) Connect wires to the transmission range sen-
sor and transmission solenoid connector. Be sure the
transmission harnesses are properly routed.
CAUTION: It is essential that correct length bolts be
used to attach the converter to the driveplate. Bolts
that are too long will damage the clutch surface
inside the converter.
(22) Install torque converter-to-driveplate bolts.
(23) Install converter housing access cover.
(24) Install starter motor and cooler line bracket.
(Refer to 8 - ELECTRICAL/STARTING/STARTER
MOTOR - INSTALLATION)
(25) Connect cooler lines (Fig. 67) to transmission.
(26) Install transmission fill tube. Install new seal
on tube before installation.(27) Install any exhaust components previously
removed.
(28) Align and connect propeller shaft. (Refer to 3 -
DIFFERENTIAL & DRIVELINE/PROPELLER
SHAFT/PROPELLER SHAFT - INSTALLATION)
(29) Adjust gearshift cable and throttle valve
cable, if necessary.
(30) Install the transfer case skid plate, if
equipped.
(31) Lower vehicle.
(32) Fill transmission with MopartATF +4, Auto-
matic Transmission fluid.
Fig. 65 Checking Converter Seating - Typical
1 - SCALE
2 - STRAIGHTEDGE
Fig. 66 Gearshift Cable At Transmission
1 - GEARSHIFT CABLE
2 - TRANSMISSION MANUAL LEVER
3 - CABLE SUPPORT BRACKET
Fig. 67 Transmission Cooler Lines
1 - TRANSMISSION
2 - RADIATOR
3 - COOLER LINES
21 - 354 AUTOMATIC TRANSMISSION - 48REDR
AUTOMATIC TRANSMISSION - 48RE (Continued)

FLUID AND FILTER
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - EFFECTS OF
INCORRECT FLUID LEVEL
A low fluid level allows the pump to take in air
along with the fluid. Air in the fluid will cause fluid
pressures to be low and develop slower than normal.
If the transmission is overfilled, the gears churn the
fluid into foam. This aerates the fluid and causing
the same conditions occurring with a low level. In
either case, air bubbles cause fluid overheating, oxi-
dation and varnish buildup which interferes with
valve and clutch operation. Foaming also causes fluid
expansion which can result in fluid overflow from the
transmission vent or fill tube. Fluid overflow can eas-
ily be mistaken for a leak if inspection is not careful.
DIAGNOSIS AND TESTING - CAUSES OF
BURNT FLUID
Burnt, discolored fluid is a result of overheating
which has two primary causes.
(1) A result of restricted fluid flow through the
main and/or auxiliary cooler. This condition is usu-
ally the result of a faulty or improperly installed
drainback valve, a damaged main cooler, or severe
restrictions in the coolers and lines caused by debris
or kinked lines.
(2) Heavy duty operation with a vehicle not prop-
erly equipped for this type of operation. Trailer tow-
ing or similar high load operation will overheat the
transmission fluid if the vehicle is improperly
equipped. Such vehicles should have an auxiliary
transmission fluid cooler, a heavy duty cooling sys-
tem, and the engine/axle ratio combination needed to
handle heavy loads.
DIAGNOSIS AND TESTING - FLUID
CONTAMINATION
Transmission fluid contamination is generally a
result of:
²adding incorrect fluid
²failure to clean dipstick and fill tube when
checking level
²engine coolant entering the fluid
²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failuredue to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transmission vent where it may be mis-
taken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
Fluid level is checked with the engine running at
curb idle speed, the transmission in NEUTRAL and
the transmission fluid at normal operating tempera-
ture.The engine should be running at idle
speed for at least one minute, with the vehicle
on level ground.
The transmission fluid level can be checked two
ways.
PROCEDURE ONE
(1) Transmission fluid must be at normal operat-
ing temperature for accurate fluid level check. Drive
DRAUTOMATIC TRANSMISSION - 48RE 21 - 381

(9) Fill the transmission with the recommended
fluid.
TORQUE CONVERTER
DRAINBACK VALVE
DESCRIPTION
The drainback valve is located in the transmission
cooler outlet (pressure) line.
OPERATION
The valve prevents fluid from draining from the
converter into the cooler and lines when the vehicleis shut down for lengthy periods. Production valves
have a hose nipple at one end, while the opposite end
is threaded for a flare fitting. All valves have an
arrow (or similar mark) to indicate direction of flow
through the valve.
STANDARD PROCEDURE - TORQUE
CONVERTER DRAINBACK VALVE
The converter drainback check valve is located in
the cooler outlet (pressure) line near the radiator
tank. The valve prevents fluid drainback when the
vehicle is parked for lengthy periods. The valve check
ball is spring loaded and has an opening pressure of
approximately 2 psi.
The valve is serviced as an assembly; it is not
repairable. Do not clean the valve if restricted, or
contaminated by sludge, or debris. If the valve fails,
or if a transmission malfunction occurs that gener-
ates significant amounts of sludge and/or clutch par-
ticles and metal shavings, the valve must be
replaced.
The valve must be removed whenever the cooler
and lines are reverse flushed. The valve can be flow
tested when necessary. The procedure is exactly the
same as for flow testing a cooler.
If the valve is restricted, installed backwards, or in
the wrong line, it will cause an overheating condition
and possible transmission failure.
CAUTION: The drainback valve is a one-way flow
device. It must be properly oriented in terms of flow
direction for the cooler to function properly. The
valve must be installed in the pressure line. Other-
wise flow will be blocked and would cause an over-
heating condition and eventual transmission failure.
Fig. 241 Typical Method Of Checking Converter
Seating
1 - SCALE
2 - STRAIGHTEDGE
21 - 440 AUTOMATIC TRANSMISSION - 48REDR
TORQUE CONVERTER (Continued)

²internal failure that generates debris
²overheat that generates sludge (fluid break-
down)
²failure to replace contaminated converter after
repair
The use of non-recommended fluids can result in
transmission failure. The usual results are erratic
shifts, slippage, abnormal wear and eventual failure
due to fluid breakdown and sludge formation. Avoid
this condition by using recommended fluids only.
The dipstick cap and fill tube should be wiped
clean before checking fluid level. Dirt, grease and
other foreign material on the cap and tube could fall
into the tube if not removed beforehand. Take the
time to wipe the cap and tube clean before withdraw-
ing the dipstick.
Engine coolant in the transmission fluid is gener-
ally caused by a cooler malfunction. The only remedy
is to replace the radiator as the cooler in the radiator
is not a serviceable part. If coolant has circulated
through the transmission, an overhaul is necessary.
The torque converter should be replaced whenever
a failure generates sludge and debris. This is neces-
sary because normal converter flushing procedures
will not remove all contaminants.
STANDARD PROCEDURE
STANDARD PROCEDURE - FLUID LEVEL
CHECK
Low fluid level can cause a variety of conditions
because it allows the pump to take in air along with
the fluid. As in any hydraulic system, air bubbles
make the fluid spongy, therefore, pressures will be
low and build up slowly.
Improper filling can also raise the fluid level too
high. When the transmssion has too much fluid, the
geartrain churns up foam and cause the same condi-
tions which occur with a low fluid level.
In either case, air bubbles can cause overheating
and/or fluid oxidation, and varnishing. This can
interfere with normal valve, clutch, and accumulator
operation. Foaming can also result in fluid escaping
from the transmission vent where it may be mis-
taken for a leak.
After the fluid has been checked, seat the dipstick
fully to seal out water and dirt.
The transmission has a dipstick to check oil level.
It is located on the right side of the engine. Be sure
to wipe all dirt from dipstick handle before removing.
The torque converter fills in both the P (PARK)
and N (NEUTRAL) positions. Place the selector lever
in P (PARK) to be sure that the fluid level check is
accurate.The engine should be running at idle
speed for at least one minute, with the vehicleon level ground.At normal operating temperature
(approximately 82 C. or 180 F.), the fluid level is cor-
rect if it is in the HOT region (cross-hatched area) on
the oil level indicator. The fluid level will be approx-
imately at the upper COLD hole of the dipstick at
70É F fluid temperature.
NOTE: Engine and Transmission should be at nor-
mal operating temperature before performing this
procedure.
(1) Start engine and apply parking brake.
(2) Shift the transmission into DRIVE for approxi-
mately 2 seconds.
(3) Shift the transmission into REVERSE for
approximately 2 seconds.
(4) Shift the transmission into PARK.
(5) Hook up DRBtscan tool and select transmis-
sion.
(6) Select sensors.
(7) Read the transmission temperature value.
(8) Compare the fluid temperature value with the
chart. (Fig. 66)
(9) Adjust transmission fluid level shown on the
dipstick according to the chart.
NOTE: After adding any fluid to the transmission,
wait a minimum of 2 minutes for the oil to fully
drain from the fill tube into the transmission before
rechecking the fluid level.
(10) Check transmission for leaks.
STANDARD PROCEDURE - FLUID AND FILTER
REPLACEMENT
For proper service intervals (Refer to LUBRICA-
TION & MAINTENANCE/MAINTENANCE SCHED-
ULES - DESCRIPTION).
REMOVAL
(1) Hoist and support vehicle on safety stands.
(2) Place a large diameter shallow drain pan
beneath the transmission pan.
(3) Remove bolts holding front and sides of pan to
transmission.
(4) Loosen bolts holding rear of pan to transmis-
sion.
(5) Slowly separate front of pan away from trans-
mission allowing the fluid to drain into drain pan.
(6) Hold up pan and remove remaining bolts hold-
ing pan to transmission.
(7) While holding pan level, lower pan away from
transmission.
(8) Pour remaining fluid in pan into drain pan.
(9) Remove screw holding filter to valve body (Fig.
67).
21 - 542 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR
FLUID AND FILTER (Continued)

Description N´m Ft. Lbs. In. Lbs.
Instrument panel top bolts 12 9 Ð
Load floor nuts 25 18 Ð
Load floor/rear seat bolts 40 30 Ð
Overhead/b-pillar grab handle bolts 6 Ð 55
Radiator and condenser to radiator crossmember bolts 8 Ð 75
Radiator upper crossmember bolts 28 21 Ð
Rear door glass lift plate nuts 10 Ð 89
Rear door glass run channels 10 Ð 89
Rear door hinge to b-pillar bolts 28 21 Ð
Rear door hinge to door bolts/nuts 28 21 Ð
Rear door inside handle bolt 9 Ð 80
Rear door latch adjustment screw 3 Ð 30
Rear door latch bolts 10 Ð 89
Rear door latch striker bolts 28 21 Ð
Rear door regulator bolts 10 Ð 89
Rear door regulator stabilizer nuts 10 Ð 89
Rear door remote handle actuator nuts 10 Ð 89
Rear fender bottom screws 7 Ð 60
Rear fender nuts 7 Ð 60
Rear fender support bracket bolts 11 8 Ð
Rear seat assembly bolts*40 30 Ð
Rear seat back hinge bolts*25 18 Ð
Rear seat cushion hinge bolts*32 24 Ð
Rear shoulder belt anchor bolts 40 30 Ð
Rear view mirror set screw 1 Ð 15
Shifter knob nut 27 20 Ð
Side view mirror nuts 7 Ð 60
Tailgate check cable bolt 23 17 Ð
Tailgate hinge/pivot screws 34 25 Ð
Tailgate latch bolts 23 17 Ð
Tailgate latch striker 34 25 Ð
Tailgate release handle nuts 7 Ð 60
NOTE: *Seat fasteners should be discarded and
replaced with new fasteners during assembly.
DRBODY 23 - 13
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.............................37
INSTALLATION.........................37
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.............................39
INSTALLATION.........................40
GRILLE FRAME
REMOVAL.............................40
INSTALLATION.........................40
FRONT WHEELHOUSE SPLASH SHIELD
REMOVAL.............................40
INSTALLATION.........................41
REAR WHEELHOUSE SPLASH SHIELD
REMOVAL.............................41
INSTALLATION.........................41
SIDE VIEW MIRROR
REMOVAL.............................41
INSTALLATION.........................41
UPPER RADIATOR CROSSMEMBER
REMOVAL.............................42
INSTALLATION.........................42
SIDE VIEW MIRROR GLASS
REMOVAL.............................42
INSTALLATION.........................44
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

UPPER RADIATOR
CROSSMEMBER
REMOVAL
(1) Remove the hood latch. (Refer to 23 - BODY/
HOOD/LATCH - REMOVAL)
(2) Remove the radiator and condenser bolts. (Fig.
14)
(3) Remove the bolts and remove the crossmember.
(Fig. 15)
INSTALLATION
(1) Install the crossmember and install the bolts.
(2) Tighten the bolts to 28 N´m (21 ft. lbs.).
(3) Install the radiator and condenser bolts and
tighten to 8 N´m (75 in. lbs.).
(4) Install the hood latch. (Refer to 23 - BODY/
HOOD/LATCH - INSTALLATION)
SIDE VIEW MIRROR GLASS
REMOVAL
WARNING: ALWAYS WEAR EYE AND HAND PRO-
TECTION WHEN SERVICING THE MIRROR ASSEM-
BLY. FAILURE TO OBSERVE THESE WARNINGS
MAY RESULT IN PERSONAL INJURY FROM BRO-
KEN GLASS.
Standard Mirror
(1) Position the mirror glass so that it's facing in
toward the vehicle as far as possible. (Fig. 16)
(2) Disengage the rear housing cover retaining
tabs and remove the cover. (Fig. 17)
(3) Disengage the lower glass retaining tab to
motor. (Fig. 18)
(4) Slide glass up and remove from motor.
(5) Disconnect the two heated mirror electrical
connectors, if equipped.
Fig. 14 CONDENSER/RADIATOR FASTENERS
1 - CONDENSER BOLT
2 - RADIATOR BOLT
3 - RADIATOR CROSSMEMBER
Fig. 15 RADIATOR CROSSMEMBER
1 - BOLTS (2)
2 - CROSSMEMBER
3 - BOLTS (2)
Fig. 16 STANDARD MIRROR POSITION
1 - RETAINING TABS (2)
2 - MIRROR HOUSING
3 - MIRROR GLASS
23 - 42 EXTERIORDR

HOOD
REMOVAL
(1) Open the hood.
(2) Using a grease pencil or equivalent, mark the
position of the hinges on the hood.
(3) Remove the hood hinge nuts and remove the
hood.
(4) Remove the grille. (Refer to 23 - BODY/EXTE-
RIOR/GRILLE - REMOVAL)
(5) Remove the hood lamp and ambient tempera-
ture sensor.
INSTALLATION
(1) Install the hood lamp and ambient temperature
sensor.
(2) Install the grille. (Refer to 23 - BODY/EXTERI-
OR/GRILLE - INSTALLATION)
(3) Install the hood and install the nuts.
(4) Line up the marks made previously and
tighten the nuts to 23 N´m (17 ft. lbs.).
(5) Check the hood fit and adjust if required.
(Refer to 23 - BODY/BODY STRUCTURE/GAP AND
FLUSH - SPECIFICATIONS)
LATCH
REMOVAL
(1) Open the hood.
(2) Using a grease pencil or equivalent, mark the
position of the latch on the radiator crossmember.
(3) Remove the bolts. (Fig. 3)
(4) Disconnect the hood latch cable and remove the
latch.
INSTALLATION
(1) Connect the hood latch cable.
(2) Install the latch lining up the marks made pre-
viously and install the bolts.
(3) Tighten the bolts to 11 N´m (8 ft. lbs.).
(4) Check hood fit and adjust if required. (Refer to
23 - BODY/BODY STRUCTURE/GAP AND FLUSH -
SPECIFICATIONS)
LATCH RELEASE CABLE/
HANDLE ASSEMBLY
REMOVAL
(1) Remove the hood latch. (Refer to 23 - BODY/
HOOD/LATCH - REMOVAL)
(2) Remove the batter tray. (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/TRAY - REMOVAL)
(3) Disconnect the three cable push pin fasteners.
(4) From inside the cab loosen the two handle
screws and disconnect the handle from the instru-
ment panel bracket.
(5) Separate the grommet at the cowl panel and
remove cable through the cab.
INSTALLATION
(1) Route the cable/handle assembly through the
cowl panel and install the grommet.
(2) Position the handle onto the instrument panel
bracket and tighten the screws.
(3) Route the cable along the fender rails and
install the three push pin fasteners.
(4) Install the latch. (Refer to 23 - BODY/HOOD/
LATCH - INSTALLATION)
(5) Install the battery tray. (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/TRAY - INSTALLATION)
Fig. 2 HINGE
1 - A-PILLAR
2 - HINGE
3 - BOLTS (2)
Fig. 3 LATCH
1 - HOOD LATCH
2 - HOOD LATCH CABLE
3 - BOLTS (2)
DRHOOD 23 - 47
HINGE (Continued)

WELD LOCATIONS
SPECIFICATIONS
INDEX
DESCRIPTION FIGURE
FENDER BRACE, CLOSURE TUBE AND FRAME MOUNTING BRACKET TO FRONT
FENDER SUPPORT, FRONT FENDER AND RADIATOR TUBE31
STEERING COLUMN SUPPORT, CONNECTOR WIRING BRACKET AND WELD NUTS
TO LOWER PLENUM PANEL32
WIPER ATTACHING WELD NUTS AND VACUUM RESERVOIR ATTACHING STUDS TO
COWL PAR PANEL33
DASH PANEL TO FRONT FLOOR PAN 34
DASH PANEL TO LOWER PLENUM PANEL 35
LOWER PLENUM PANEL TO COWL BACK PANEL 36
FRONT FENDER AND RADIATOR TUBE DASH PANEL, INSTRUMENT PANEL
MOUNTING BRACKET, AND WELD NUTS TO COWL SIDE PANEL - LEFT SIDE37
DASH PANEL, LOWER PLENUM PANEL AND COWL PANEL BAR TO COWL SIDE
PANEL - LEFT SIDE38
FRONT FENDER AND RADIATOR TUBE DASH PANEL, INSTRUMENT PANEL
MOUNTING BRACKET AND WELD NUTS TO COWL SIDE PANEL - RIGHT SIDE39
DASH PANEL, LOWER PLENUM PANEL AND COWL PANEL BAR TO COWL SIDE
PANEL - RIGHT SIDE40
REINFORCEMENT AND HEADLAMP MOUNTING PANEL TO OUTER FENDER PANEL 41
SEAT MOUNTING FRONT BRACKETS TO SEAT MOUNTING FRONT CROSSMEMBER
TO FRONT FLOOR PAN42
AIR BAG MODULE BRACKET SHIFTER MOUNTING PLATE AND REAR FLOOR PANE
TO FRONT FLOOR PAN43
RIGHT TO LEFT REAR FLOOR CROSSMEMBER AND RIGHT TO LEFT SEAT
MOUNTING CROSSMEMBER44
REAR FLOOR CROSSMEMBER, SEAT MOUNTING CROSSMEMBER AND
UNDERBODY SUPPORT TO FLOOR SILL45
SEAT MOUNTING FRONT CROSSMEMBER TO FRONT FLOOR PAN TO UNDERBODY
SUPPORT46
FRONT SEAT MOUNTING CROSSMEMBERS TO FRONT SEAT MOUNTING BRACKET
TO FRONT FLOOR PAN47
REAR FLOOR CROSSMEMBERS TO REAR FLOOR PAN 48
FLOOR SILL TO FRONT SEAT MOUNTING CROSSMEMBER, FRONT AND REAR
FLOOR PAN49
AIR BAG MODULE BRACKET, SHIFTER MOUNTING PLATE AND FRONT SEAT
MOUNTING CROSSMEMBER TO FRONT FLOOR PAN50
REAR SEAT MIDDLE MOUNTING PLATE TO REAR FLOOR PAN TO FRONT FLOOR
PA N51
REAR FLOOR CROSSMEMBER, SEAT MOUNTING CROSSMEMBER AND
UNDERBODY SUPPORT TO FLOOR SILL52
LEFT REAR CROSSMEMBER TO RIGHT REAR CROSSMEMBER TO REAR FLOOR
PA N53
23 - 122 BODY STRUCTUREDR

HEATING & AIR CONDITIONING
TABLE OF CONTENTS
page page
HEATING & AIR CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER........................1
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS.......................1
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT........................1
OPERATION
OPERATION - HEATER AND AIR
CONDITIONER........................1
OPERATION - REFRIGERANT SYSTEM
SERVICE PORT........................2DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - A/C
PERFORMANCE.......................2
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE.......................5
STANDARD PROCEDURE - DIODE
REPLACEMENT.......................7
SPECIFICATIONS
A/C APPLICATION TABLE................7
SPECIFICATIONS......................8
CONTROLS.............................9
DISTRIBUTION..........................24
PLUMBING.............................31
HEATING & AIR
CONDITIONING
DESCRIPTION
DESCRIPTION - HEATER AND AIR
CONDITIONER
All vehicles are equipped with a common HVAC
housing assembly (Fig. 1). The system combines air
conditioning, heating, and ventilating capabilities in
a single unit housing mounted under the instrument
panel.
DESCRIPTION - COOLING SYSTEM
REQUIREMENTS
To maintain the performance level of the HVAC
system, the engine cooling system must be properly
maintained. The use of a bug screen is not recom-
mended. Any obstructions in front of the radiator or
condenser will reduce the performance of the air con-
ditioning and engine cooling systems.
The engine cooling system includes the heater core
and the heater hoses. Refer to Engine Cooling for
more information before the opening of, or attempt-
ing any service to the engine cooling system.
DESCRIPTION - REFRIGERANT SYSTEM
SERVICE PORT
The two refrigerant system service ports are used
to charge, recover/recycle, evacuate, and test the air
conditioning refrigerant system. Unique service port
coupler sizes are used on the R-134a system, toensure that the refrigerant system is not accidentally
contaminated by the use of the wrong refrigerant
(R-12), or refrigerant system service equipment.
OPERATION
OPERATION - HEATER AND AIR CONDITIONER
The heater air conditioner are blend-air type sys-
tems. In a blend-air system, a blend door controls the
amount of unconditioned air (or cooled air from the
evaporator on models with air conditioning) that is
allowed to flow through, or around, the heater core. A
temperature control knob on the A/C Heater control
panel determines the discharge air temperature by
controlling an electric actuator, which moves the
blend door. This allows an almost immediate control
of the output air temperature of the system.
The mode control knob on the A/C Heater control
panel is used to direct the conditioned air to the
selected system outlets. Both mode control switches
use electric actuators to control the mode doors.
On all vehicles, the outside air intake can be shut
off by selecting the Recirculation Mode with the
mode control knob. This will operate a electric actu-
ated recirculation door that closes off the outside
fresh air intake and recirculates the air that is
already inside the vehicle.
The air conditioner for all models is designed for
the use of non-CFC, R-134a refrigerant. The air con-
ditioning system has an evaporator to cool and dehu-
midify the incoming air prior to blending it with the
heated air. This air conditioning system uses a fixed
orifice tube in the liquid line near the condenser out-
let tube to meter refrigerant flow to the evaporator
DRHEATING & AIR CONDITIONING 24 - 1