RADIATOR DODGE RAM 1500 1998 2.G Workshop Manual

(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 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 also be replaced when-
ever a failure generates sludge and debris. This is
necessary because normal converter flushing proce-
dures 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, thegeartrain 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
vehicle if necessary to bring fluid temperature up to
normal hot operating temperature of 82ÉC (180ÉF).
(2) Position vehicle on level surface.
(3) Start and run engine at curb idle speed.
(4) Apply parking brakes.
(5) Shift transmission momentarily into all gear
ranges. Then shift transmission back to NEUTRAL.
(6) Clean top of filler tube and dipstick to keep
dirt from entering tube.
(7) Remove dipstick (Fig. 87) and check fluid level
as follows:
(a) Correct acceptable level is in crosshatch area.
(b) Correct maximum level is to MAX arrow
mark.
(c) Incorrect level is at or below MIN line.
(d) If fluid is low, add only enough MopartAT F
+4 to restore correct level. Do not overfill.
Fig. 87 Dipstick Fluid Level Marks - Typical
1 - DIPSTICK
2 - MAXIMUM CORRECT FLUID LEVEL
3 - ACCEPTABLE FLUID LEVEL
21 - 202 AUTOMATIC TRANSMISSION - 48REDR
FLUID AND FILTER (Continued)

(6) Check converter seating with a scale and
straightedge (Fig. 235). Surface of converter lugs
should be 19mm (0.75 in.) to the rear of the straight-
edge when converter is fully seated.
(7) If necessary, temporarily secure converter with
C-clamp attached to the converter housing.
(8) Install the transmission in the vehicle.
(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 vehicle
is 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.
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.
TOW/HAUL OVERDRIVE
SWITCH
DESCRIPTION
The tow/haul overdrive OFF (control) switch is
located in the shift lever arm (Fig. 236). The switch
is a momentary contact device that signals the PCM
to toggle current status of the overdrive function.
Fig. 235 Typical Method Of Checking Converter
Seating
1 - SCALE
2 - STRAIGHTEDGE
Fig. 236 Tow/Haul Overdrive Off Switch
DRAUTOMATIC TRANSMISSION - 48RE 21 - 261
TORQUE CONVERTER (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 three primary causes.
(1) Internal clutch slippage, usually caused by low
line pressure, inadequate clutch apply pressure, or
clutch seal failure.
(2) 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.
(3) 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
repairThe 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 also be replaced when-
ever a failure generates sludge and debris. This is
necessary because normal converter flushing proce-
dures 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 vehicle
on 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-
21 - 366 AUTOMATIC TRANSMISSION - 45RFE/545RFEDR

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
Lower seat belt anchor bolt - quad cab 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.............................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

INSTALLATION
(1) Install the mirror onto the door and engage the
electrical connector tabs. (Fig. 13)
(2) Install the nuts and tighten to 7 N´m (60 in.
lbs.).
(3) Install the door trim panel. (Refer to 23 -
BODY/DOOR - FRONT/TRIM PANEL - INSTALLA-
TION)
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)
Fig. 13 MIRROR ELECTRICAL CONNECTOR
1 - DOOR
2 - MIRROR STUDS
3 - CONNECTOR TABS
4 - ELECTRICAL CONNECTOR
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)
23 - 42 EXTERIORDR
SIDE VIEW MIRROR (Continued)

(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)
LATCH STRIKER /
SECONDARY CATCH
REMOVAL
(1) Disconnect and remove the secondary release
handle. (Fig. 4)
(2) Remove the two bolts and remove the striker/
catch assembly.
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
HOOD (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 - 120 BODY STRUCTUREDR

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

Condition Possible Causes Correction
The low side pressure is too
low, and the high side
pressure is too high.1. Restricted refrigerant flow
through the refrigerant lines.1. See Liquid, Suction, and Discharge Line in this
group. Inspect the refrigerant lines for kinks, tight
bends or improper routing. Correct the routing or
replace the refrigerant line, if required.
2. Restricted refrigerant flow
through the fixed orifice tube.2. See A/C Orifice Tube in this group. Replace
the liquid line, if required.
3. Restricted refrigerant flow
through the condenser.3. See A/C Condenser in this group. Replace the
restricted condenser, if required.
DIAGNOSIS AND TESTING - HEATER
PERFORMANCE TEST
Review Safety Warnings and Cautions before per-
forming this procedure (Refer to 24 - HEATING &
AIR CONDITIONING/PLUMBING - WARNING) and
(Refer to 24 - HEATING & AIR CONDITIONING/
PLUMBING - CAUTION).
Check the coolant level, drive belt tension, vacuum
line connections, radiator air flow and fan operation.
Start engine and allow to warm up to normal tem-
perature.
WARNING: DO NOT REMOVE RADIATOR CAP
WHEN ENGINE IS HOT, PERSONAL INJURY CAN
RESULT.
If vehicle has been run recently, wait 15 minutes
before removing cap. Place a rag over the cap andturn it to the first safety stop. Allow pressure to
escape through the overflow tube. When the system
stabilizes, remove the cap completely.
MAXIMUM HEATER OUTPUT: TEST AND ACTION
Engine coolant is provided to the heater system by
two heater hoses. With the engine idling at normal
operating temperature, set the temperature control
to maximum heat, the mode control to the floor posi-
tion, and the blower in the highest speed position.
Using a test thermometer, check the temperature of
the air being discharged from the floor outlets. Com-
pare the test thermometer reading to the Tempera-
ture Reference chart.
TEMPERATURE REFERENCE CHART
Ambient Air Temperature15.5É C
(60É F)21.1É C
(70É F)26.6É C
(80É F)32.2É C
(90É F)
Minimum Air Temperature at
Floor Outlet62.2É C
(144É F)63.8É C
(147É F)65.5É C
(150É F)67.2É C
(153É F)
Both of the heater hoses should be HOT to the
touch (coolant return hose should be slightly cooler
than the supply hose). If the coolant return hose is
much cooler than the supply hose, locate and repair
the engine coolant flow obstruction in the heater sys-
tem. If both heater hoses are cool to the touch,
inspect the engine cooling system (Refer to 7 -
COOLING - DIAGNOSIS AND TESTING).
OBSTRUCTED COOLANT FLOW Possible loca-
tions or causes of obstructed coolant flow are as fol-
lows:
²Pinched or kinked heater hoses.
²Improper heater hose routing.
²Plugged heater hoses or supply and return ports
at the cooling system connections.
²Plugged heater core.If proper coolant flow through the cooling system is
verified, and heater outlet air temperature is insuffi-
cient, a mechanical problem may exist.
MECHANICAL PROBLEMS Possible causes of
insufficient heat due to mechanical problems are as
follows:
²Obstructed cowl air intake.
²Obstructed heater system outlets.
²Blend door not functioning properly.
TEMPERATURE CONTROL
If the heater outlet air temperature cannot be
adjusted with the temperature control knob on the
A/C-heater control, the following could require ser-
vice:
²Blend door binding.
²Faulty blend door motor.
24 - 6 HEATING & AIR CONDITIONINGDR
HEATING & AIR CONDITIONING (Continued)