heating JEEP YJ 1995 Service And Owner's Guide

EXTENDED IDLE SWITCH TEST
OPTIONAL POLICE PACKAGE ONLY
OPERATION
The extended idle switch is used to raise the en-
gine idle speed to approximately 1000 rpm when the
shifter is in either the Park or Neutral position. A
rocker-type 2-wire switch (extended idle switch) is
mounted to the instrument panel.This switch is
available only with 4.0L engine when supplied
with the optional police package.
TESTING
The extended idle switch will control a ground cir-
cuit going to the powertrain control module (PCM).
When a ground signal (through this switch) has been
received at pin number 10 in the PCM, engine idle
speed will increase.
Bring the engine to normal operating temperature
and turn the extended idle switch to the ON position.
Engine speed should now increase to approximately
1000 rpm when the shifter is in either the Park or
Neutral position. If engine speed does not increase,
apply a good ground to pin number 10 at the PCM
using a small paper clip. Be careful not to damage
the wiring with the paper clip. If the engine speed
now increases, it can be assumed that the PCM is
functioning correctly. Check the instrument panel
mounted switch for a closed ground circuit when in
the ON position. If the engine speed will not increase
after applying a ground to pin number 10, replace
the PCM. Refer to Group 8W, Wiring Diagrams for
circuit and wiring information.
THROTTLE POSITION SENSOR (TPS) TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual. To test the
sensor only, refer to the following:
The throttle position sensor (TPS) can be tested
with a digital voltmeter. The center terminal of the
TPS is the output terminal (Figs. 38 or 39).
With the ignition key in the ON position, back-
probe the TPS connector. Check the TPS output volt-
age at the center terminal wire of the connector.
Check this at idle (throttle plate closed) and at wide
open throttle (WOT). At idle, TPS output voltage
should must be greater than 200 millivolts. At wide
open throttle, TPS output voltage must be less than
4.8 volts. The output voltage should increase gradu-
ally as the throttle plate is slowly opened from idle to
WOT.
TORQUE CONVERTER CLUTCH RELAY TEST
To test the relay only, refer to RelaysÐOperation/
Testing in this section of the group. To test the
torque converter clutch circuit and related compo-nents, refer to the appropriate Powertrain Diagnostic
Procedures manual for operation of the DRB scan
tool.
VEHICLE SPEED SENSOR TEST
To perform a complete test of the sensor and its cir-
cuitry, refer to DRB scan tool and appropriate Pow-
ertrain Diagnostics Procedures manual.
OXYGEN SENSOR (O2S) HEATING ELEMENT TEST
To perform a complete test of the O2S sensor (Fig.
40) and its circuitry, refer to DRB scan tool and ap-
propriate Powertrain Diagnostics Procedures manual.
To test the sensor only, refer to the following:
The oxygen sensor heating element can be tested
with an ohmmeter as follows:
With the sensor at room temperature 25 degrees C
(77 degrees F), disconnect the O2S sensor connector.
Connect the ohmmeter test leads across the white
wire terminals of the sensor connector. Resistance
should be between 5 and 7 ohms. Replace the sensor
if the ohmmeter displays an infinity (open) reading.
Fig. 38 TPS TestingÐ2.5L Engine
Fig. 39 TPS TestingÐ4.0L Engine
14 - 48 FUEL SYSTEM GENERAL DIAGNOSISJ

(4) Tighten fittings at pump and gear to 28 Nzm
(21 ft. lbs.) torque.
(5) After installation, add power steering fluid, in-
spect and test for fluid leaks.
PUMP REPLACEMENT
REMOVAL
(1) Remove and cap pressure and return lines from
pump. Refer to Pressure and Return Line Replace-
ment in this section.(2) Remove belt tension, turn tensioner clock-wise
and slip belt off pulley (Fig. 6).
(3) Remove the screws retaining front bracket and
pump to the rear bracket (Fig. 7, 8).
(4) Remove screws that attach the front bracket to
the rear bracket (Fig. 9).
(5) Remove pump from bracket.
To remove the rear bracket from engine, the air
conditioning compressor and bracket must be re-
moved first. Refer to Group 24, Heating and Air Con-
ditioning for removal procedures.
(6) Remove fan from pulley and hub on rear
bracket.
(7) Remove 4 screws attaching the rear bracket to
block (Fig. 10, 11).
(8) Remove bracket from engine.
Fig. 6 Belt Tensioner
Fig. 7 Pump Mounting Screw Removal/Installation
Fig. 8 Power Steering Pump Mounting
Fig. 9 Front Bracket
19 - 76 STEERINGJ

INSTALLATION
(1) Install the rear bracket to engine. Install
screws finger tight.
(2) Tighten front screws to 48 Nzm (35 ft. lbs.)
torque. Tighten side screw to 48 Nzm (35 ft. lbs.)
torque. It is important to torque the front screws
FIRST and the side screw LAST. This will prevent
the bracket from twisting or distorting.
(3) Install fan to pulley and hub. Tighten the nuts
to 27 Nzm (20 ft. lbs.) torque.
(4) Install air conditioning bracket and compressor
to engine. Refer to Group 24, Heating and Air Condi-
tioning for installation procedures.(5) Loose assemble screws through front bracket,
pump and into rear bracket.
(6) Install screws that attach the front bracket to
the rear bracket (Fig. 8). Tighten the screws to 27
Nzm (20 ft. lbs.) torque (Fig. 7).
(7) Install belt, turn tensioner clockwise and slip
belt onto pulley (Fig. 6).
(8) Install pressure and return lines to pump. Re-
fer to Pressure and Return Line Replacement in this
section.
(9) After installation, add power steering fluid, in-
spect and test for fluid leaks. Refer to Power Steering
PumpÐInitial Operation.
Fig. 11 Rear Bracket (Side View)Fig. 10 Rear Bracket (Front View)
JSTEERING 19 - 77

happens when the container delivery mechanism is im-
properly calibrated. Always check the lubricant level af-
ter filling to avoid an under fill condition.
A correct lubricant level check can only be made
when the vehicle is level; use a drive-on hoist to en-
sure this. Also allow the lubricant to settle for a
minute or so before checking. These recommenda-
tions will ensure an accurate check and avoid an un-
der-or-overfill condition.
HARD SHIFTING
Hard shifting is usually caused by a low lubricant
level, improper or contaminated lubricants, compo-
nent damage, incorrect clutch adjustment, or by a
damaged clutch pressure plate or disc.
Substantial lubricant leaks can result in gear, shift
rail, synchro and bearing damage. If a leak goes un-
detected for an extended period, the first indications
of a problem are usually hard shifting and noise.
Incorrect or contaminated lubricants can also con-
tribute to hard shifting. The consequence of using
non-recommended lubricants is noise, excessive wear,
internal bind and hard shifting.
Improper clutch release is a frequent cause of hard
shifting. Incorrect adjustment or a worn, damaged
pressure plate or disc can cause incorrect release. If
the clutch problem is advanced, gear clash during
shifts can result.
Worn or damaged synchro rings can cause gear clash
when shifting into any forward gear. In some new or re-
built transmissions, new synchro rings may tend to
stick slightly causing hard or noisy shifts. In most
cases, this condition will decline as the rings wear-in.
TRANSMISSION NOISE
Most manual transmissions make some noise dur-
ing normal operation. Rotating gears generate a mild
whine that is audible but only at extreme speeds.
Severe, highly audible transmission noise is gener-
ally the result of a lubricant problem. Insufficient,
improper, or contaminated lubricant will promote
rapid wear of gears, synchros, shift rails, forks and
bearings. The overheating caused by a lubricant
problem, can also lead to gear breakage.
TRANSMISSION REMOVAL
(1) Shift transmission into first or third gear. Then
raise vehicle on hoist.
(2) Support engine with adjustable jack stand. Po-
sition wood block between jack and oil pan to avoid
damaging pan.
(3) Disconnect necessary exhaust system components.
(4) Remove skid plate.
(5) Disconnect rear cushion and bracket from
transmission (Fig. 5).
(6) Remove rear crossmember.
Fig. 5 Rear Mount Components (YJ Shown)
JAX 4/5 MANUAL TRANSMISSION 21 - 3

generally happens when the container delivery mech-
anism is improperly calibrated. Always check the lu-
bricant level after filling to avoid an under fill
condition.
A correct lubricant level check can only be made
when the vehicle is level; use a drive-on hoist to en-
sure this. Also allow the lubricant to settle for a
minute or so before checking. These recommenda-
tions will ensure an accurate check and avoid an un-
der-or-overfill condition.
HARD SHIFTING
Hard shifting is usually caused by a low lubricant
level, improper or contaminated lubricants, compo-
nent damage, incorrect clutch adjustment, or by a
damaged clutch pressure plate or disc.
Substantial lubricant leaks can result in gear, shift
rail, synchro and bearing damage. If a leak goes un-
detected for an extended period, the first indications
of a problem are usually hard shifting and noise.
Incorrect or contaminated lubricants can also con-
tribute to hard shifting. The consequence of using
non-recommended lubricants is noise, excessive wear,
internal bind and hard shifting.
Improper clutch release is a frequent cause of hard
shifting. Incorrect adjustment or a worn, damagedpressure plate or disc can cause incorrect release. If
the clutch problem is advanced, gear clash during
shifts can result.
Worn or damaged synchro rings can cause gear clash
when shifting into any forward gear. In some new or re-
built transmissions, new synchro rings may tend to
stick slightly causing hard or noisy shifts. In most
cases, this condition will decline as the rings wear-in.
TRANSMISSION NOISE
Most manual transmissions make some noise during
normal operation. Rotating gears can generate a mild
whine that may only be audible at extreme speeds.
Severe, obviously audible transmission noise is
generally the result of a lubricant problem. Insuffi-
cient, improper, or contaminated lubricant can pro-
mote rapid wear of gears, synchros, shift rails, forks
and bearings. The overheating caused by a lubricant
problem, can also lead to gear breakage.
TRANSMISSION REMOVAL
(1) Shift transmission into first or third gear.
(2) Raise vehicle on a hoist.
(3) Disconnect necessary exhaust system components.
(4) Support transmission with adjustable jack stand.
(5) Disconnect rear cushion and mounting bracket
from transmission, or transfer case (Fig. 1).
Fig. 1 Rear Mount Components (YJ Shown)
JAX 15 MANUAL TRANSMISSION 21 - 35

(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 and check fluid level as fol-
lows:
(a) Dipstick has three fluid level indicator levels
(Fig. 1) which are: a MIN dot, an OK crosshatch
area, and a MAX fill arrow.
(b) Correct maximum level is to MAX arrow
mark. Correct acceptable level is to OK mark in
crosshatch area.
(c) Incorrect level is at or below MIN dot.
(d) If fluid is low, add only enough Mopar ATF
Plus to restore correct level. Do not overfill.
CAUTION: Do not overfill the transmission. Overfill-
ing may cause leakage out the pump vent which
can be mistaken for a pump seal leak. Overfilling
will also cause fluid aeration and foaming as the ex-
cess fluid is picked up and churned by the gear
train. This will significantly reduce fluid life.
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 causing the
same conditions that occur with a low level.
In either case, air bubbles cause fluid overheating,
oxidation and varnish buildup which interferes with
valve, clutch and servo operation. Foaming also
causes fluid expansion which can result in fluid over-
flow from the transmission vent or fill tube. Fluid
overflow can easily be mistaken for a leak if inspec-
tion is not careful.
TRANSMISSION THROTTLE VALVE CABLE
ADJUSTMENT
Throttle cable adjustment is important to proper
operation. This adjustment positions the throttle
valve which controls shift speed, quality and part
throttle downshift sensitivity.
If cable adjustment setting is too short, early shifts
and slippage between shifts may occur. If the setting
is too long, shifts may be delayed and part throttle
downshifts may be very sensitive. Refer to the In-Ve-
hicle Service section for adjustment procedure.
GEARSHIFT CABLE/LINKAGE ADJUSTMENT
Gearshift cable/linkage adjustment is important be-
cause it positions the valve body manual valve. Incor-
rect adjustment will cause creeping in Neutral,
premature clutch wear, delayed engagement in any
gear, or a no-start in Park or Neutral position.Proper operation of the neutral start switch will
provide a quick check on adjustment. Refer to the In-
Vehicle Service section for adjustment procedure.
ROAD TEST
Before road testing, be sure the fluid level and all
cable/linkage adjustments have been checked and ad-
justed if necessary.
Observe engine performance during the road test. A
poorly tuned engine will not allow an accurate anal-
ysis of transmission operation.
Operate the transmission in all gear ranges. Check
for slippage and shift variations. Note whether the
shifts are harsh, spongy, delayed, early, or if part
throttle downshifts are sensitive.
Watch closely for slippage or engine flare which
usually indicates clutch, band or overrunning clutch
problems. If the condition is advanced, an overhaul
may be necessary to restore normal operation.
A slipping clutch or band can often be determined
by comparing which internal units are applied in the
various gear ranges. The Clutch and Band Applica-
tion chart (Fig. 3) provides a basis for analyzing road
test results.
ANALYZING THE ROAD TEST
Refer to the Clutch and Band Application chart
(Fig. 3) and note which elements are in use in the
various gear ranges.
The rear clutch is applied in all forward ranges (D,
2, 1). The overrunning clutch is applied in first gear
(D and 2 range only). The rear band is applied in 1
and R range only.
For example: If slippage occurs in first gear in D
and 2 range but not in 1 range, the overrunning
Fig. 3 Clutch And Band Application Chart
J30RH/32RH TRANSMISSION DIAGNOSIS 21 - 71

CONNECTING COOLER LINES AND FITTINGS
(ALL TYPES)
(1) Wipe cooler line and fitting clean with shop
towel.
(2) Insert cooler line into fitting. Then push line
inward until retainer or insert secures line. A snap or
click sound will be heard when the insert tabs or re-
tainer clip seats behind the cooler line flange.
(3)Pull outward on cooler lines/fittings to
verify they are properly secured.
CAUTION: The wire retainer clips or insert release
tabs secure the cooler lines. If the clips or tabs are
deformed, distorted, or not fully seated, normal
fluid pressure could unseat the lines resulting in
fluid loss and transmission damage. Be very sure
the cooler lines are firmly secured as described in
step (3).
CONVERTER DRAINBACK CHECK VALVE SERVICE
The converter drainback check valve is located in
the cooler outlet (pressure) line near the radiator
lower 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 pres-
sure of approximately 2 psi. Refer to the cooler flow
test procedure for valve testing.
The valve is serviced as an assembly; it is not re-
pairable. Do not clean the valve if restricted, or con-
taminated by sludge, or debris. If the valve fails, or if
a transmission malfunction occurs that generates
sludge and/or clutch particles 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 overheat condition
and possible transmission failure.
CAUTION: The drainback valve is a one-way valve.
As such, it must be properly oriented in terms of
flow direction. In addition, the valve must only beinstalled in the pressure line. Otherwise flow will be
blocked causing overheat and eventual transmis-
sion failure.
TRANSMISSION COOLER FLOW TESTING
The transmission main and auxiliary coolers, plus
the drainback valve, should be flow tested whenever
fluid overheating is noted.
Restricted flow caused by contamination, or a
cooler malfunction, reduces lubrication fluid flow
throughout the transmission. This can result in fluid
overheating, fluid breakdown, bushing wear, shift
problems and component failure.
Normal color of transmission fluid varies from
bright red, to light pink. Fluid overheating is indi-
cated when fluid color ranges from orange-brown to
black, and the fluid smells burned, or contains
sludge.
CAUTION: If a transmission malfunction contami-
nates the fluid with clutch disc and metal particles,
the cooler and lines must be reverse flushed thor-
oughly. Flushing will prevent sludge and particles
from flowing back into the transmission and con-
verter after repair.
Cooler flow is tested by measuring the amount of
fluid pumped through the cooler in a specified time
by the transmission oil pump.The same flow test
procedure is used for the drainback valve, main
cooler, and auxiliary cooler.
Cooler And Drainback Valve Flow Test Procedure
(1) Test flow throughdrainback valveas follows:
(a) Add extra quart of ATF Plus to transmission.
(b) Disconnect pressure line at radiator fitting, or
at drainback valve and position hose or valve end
in one quart test container.
(c) Shift transmission into neutral, run engine at
idle speed for 20 seconds, and note flow from valve.
Use stopwatch to check test time.
(d) Replace drainback valve if flow is less than
one quart in 20 seconds, is intermittent, or does
not flow at all.
(e) Connect pressure hose to radiator fitting and
proceed to cooler flow test.
(2) Test flow throughmain cooleras follows:
(a) Disconnect cooler return (rear) line at trans-
mission and place it in one quart test container.
(b) Add extra quart of fluid to transmission.
(c) Shift transmission into neutral, run engine at
idle speed for 20 seconds, and note flow from valve.
Use stopwatch to check test time.
(d) Replace cooler if fluid flow is less than one
quart in 20 seconds, is intermittent, or does not
flow at all.
Fig. 33 New Style Fitting Insert (On Cooler Line)
J30RH/32RH IN-VEHICLE SERVICE 21 - 113

WHEELS
GENERAL INFORMATION
Original equipment wheels are designed for the
specified Maximum Vehicle Capacity.
All models use steel or cast aluminum drop center
wheels. The safety rim wheel (Fig. 1) has raised sec-
tions between the rim flanges and the rim well.
Initial inflation of the tire forces the bead over
these raised sections. In case of tire failure, the
raised sections 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 and alignment equipment.
WHEEL INSTALLATION
The wheel studs and nuts are designed for specific
applications. They must be replaced with equivalent
parts. Do not use replacement parts of lesser quality
or a substitute design. All aluminum and some steel
wheels have wheel stud nuts which feature an en-
larged nose. This enlarged nose is necessary to en-
sure proper retention of the aluminum wheels.
Before installing the wheel, be sure to remove any
build up of corrosion on the wheel mounting surfaces.
Ensure wheels are installed with good metal-to-metal
contact. Improper installation could cause loosening
of wheel nuts. This could affect the safety and han-
dling of your vehicle.
To install the wheel, first position it properly on
the mounting surface. All wheel nuts should then be
tightened just snug. Gradually tighten them in se-
quence to 129 Nzm (95 ft. lbs.) torque (Fig. 2).Never
use oil or grease on studs or nuts.
WHEEL REPLACEMENT
Wheels must be replaced if they have:²Excessive runout
²Bent or dented
²Leak air through welds
²Have damaged bolt holes
Wheel repairs employing hammering, heating, or
welding are not allowed.
Original equipment wheels are available through
your dealer. Replacement wheels from any other
source should be equivalent in:
²Load carrying capacity
²Diameter
²Width
²Offset
²Mounting configuration
Failure to use equivalent replacement wheels may
affect the safety and handling of your vehicle. Re-
placement withusedwheels is not recommended.
Their service history may have included severe treat-
ment.
Refer to the Specifications Chart for informa-
tion regarding above requirements.
WHEEL ORNAMENTATION
WARNING: HANDLE ALL WHEEL ORNAMENTATION
WITH EXTREME CARE DURING REMOVAL AND IN-
STALLATION. SHARP EDGES ON THE COVERS OR
CAPS CAN CAUSE PERSONAL INJURY.
TIRE AND WHEEL BALANCE
It is recommended that a two plane dynamic bal-
ancer be used when a wheel and tire assembly re-
quire balancing. Static should be used only when a
two plane balancer is not available.
For static imbalance, find location of heavy spot
causing imbalance. Counter balance wheel directly
Fig. 1 Wheel Safety Rim
Fig. 2 Lug Nut Tightening Pattern
22 - 6 WHEELS AND TIRESJ

(5) Remove the retaining screws and the air intake
adapters from the grille panel (Fig. 6).
(6) Remove the bolts and washers that attach the
grille panel to the fenders (Fig. 7).
(7) Remove the bolts, washers and spacers that at-
tach the grille panel to the front crossmember (Fig.
8).
(8) Remove the nuts that attach the radiator sup-
port rods to the front brackets (Fig. 9). Remove the
rods from the brackets.
(9) Tilt the grille panel forward and disconnect the
head lamp, turn signal and marker lamp wire har-
ness connectors.
(10) For vehicles equipped with A/C, discharge the
A/C system. Disconnect the high pressure hose at the
sight glass connection and at the compressor. Cap thehose and fittings to prevent foreign material entry. If
necessary, refer to Group 24ÐHeating And Air Con-
ditioning.
(11) Remove the grille panel from the vehicle (Fig.
8).
(12) If a replacement radiator grille panel will be
installed, remove the grille applique (Fig. 8) and
transfer the lamps, the headlamp buckets and the re-
taining brackets.
Fig. 7 Grille Panel Front Bolt
Fig. 8 Radiator Grille Applique and Grille Panel
Fig. 6 Air Intake and Radiator Baffle Adapters
23 - 106 EXTERIOR COMPONENTSÐYJJ

HEATING AND AIR CONDITIONING
CONTENTS
page page
COMPONENT SERVICEÐXJ VEHICLES...... 23
COMPONENT SERVICEÐYJ VEHICLES...... 32
COMPRESSOR SERVICE.................. 19
GENERAL INFORMATION.................. 1
HEATING AND AIR CONDITIONING TEST
PROCEDURES......................... 15REFRIGERANT SERVICE AND PERFORMANCE
TEST................................ 11
TORQUE SPECIFICATIONS................ 37
WARNINGS, CAUTIONS AND SERVICE
PRECAUTIONS......................... 9
GENERAL INFORMATION
INDEX
page page
A/C Components.......................... 4
Heater and A/C Operation.................... 1
Manifold Gauge Set........................ 7Refrigerant............................... 7
Refrigerant Equipment...................... 7
HEATER AND A/C OPERATION
HEATERÐXJ
A blend-air heating system is used in XJ vehicles.
The temperature of heated air is controlled by regu-
lating the quantity of air flow through the heater
core. This is accomplished by blending outside air
with heated air from the heater core to obtain the de-
sired discharge temperature. A temperature control
lever on the heater control determines air flow
through the heater core. The lever uses a cable to op-erate the blend-air door. This door controls air flow
through the core. Vacuum motors are used to actuate
and position the remaining door in the system.
On left hand drive (LHD) XJ vehicles a water valve
controls coolant flow to the heater core. The valve is
vacuum operated. When vacuum is applied, the valve
opens and coolant is directed through the heater core
and back to the engine. When the water valve is
closed (no vacuum applied) coolant flow bypasses the
heater core back to the engine.
JHEATING AND AIR CONDITIONING 24 - 1