2002 JEEP GRAND CHEROKEE Time set

INSTALLATION........................253
OUTPUT SPEED SENSOR
DESCRIPTION........................254
OPERATION..........................254
REMOVAL............................254
INSTALLATION........................254
OVERDRIVE SWITCH
DESCRIPTION........................254
OPERATION..........................254
PARK LOCK CABLE
REMOVAL............................255
INSTALLATION........................255
PISTONS
DESCRIPTION........................256
OPERATION..........................256
PLANETARY GEARTRAIN
DESCRIPTION........................258
OPERATION..........................260
DISASSEMBLY........................260
CLEANING...........................260
INSPECTION.........................260
ASSEMBLY...........................261
SHIFT MECHANISM
DESCRIPTION........................261
OPERATION..........................261
REMOVAL............................261
INSTALLATION........................263
SOLENOID SWITCH VALVE
DESCRIPTION........................263
OPERATION..........................263
SOLENOIDS
DESCRIPTION........................263OPERATION..........................264
TORQUE CONVERTER
DESCRIPTION........................264
OPERATION..........................268
REMOVAL............................269
INSTALLATION........................269
TRANSMISSION CONTROL RELAY
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION RANGE SENSOR
DESCRIPTION........................270
OPERATION..........................270
TRANSMISSION SOLENOID/TRS ASSEMBLY
DESCRIPTION........................271
OPERATION..........................271
REMOVAL............................272
INSTALLATION........................272
TRANSMISSION TEMPERATURE SENSOR
DESCRIPTION........................272
OPERATION..........................272
VALVE BODY
DESCRIPTION........................273
OPERATION..........................273
REMOVAL............................274
DISASSEMBLY........................275
CLEANING...........................277
INSPECTION.........................277
ASSEMBLY...........................278
INSTALLATION........................279
AUTOMATIC TRANSMISSION -
545RFE
DESCRIPTION
The 545RFE automatic transmission is a sophisti-
cated, multi-range, electronically controlled transmis-
sion which combines optimized gear ratios for
responsive performance, state of the art efficiency
features and low NVH. Other features include driver
adaptive shifting and three planetary gear sets to
provide wide ratio capability with precise ratio steps
for optimum driveability. The three planetary gear
sets also make available a unique alternate second
gear ratio. The primary 2nd gear ratio fits between
1st and 3rd gears for normal through-gear accelera-
tions. The alternate second gear ratio (2prime) allows
smoother 4-2 kickdowns at high speeds to provide
2nd gear passing performance over a wider highway
cruising range. An additional overdrive ratio (0.67:1)
is also provided for greater fuel economy and less
NVH at highway speeds.The hydraulic portion of the transmission consists
of the transmission fluid, fluid passages, hydraulic
valves, and various line pressure control components.
The primary mechanical components of the trans-
mission consist of the following:
²Three multiple disc input clutches
²Three multiple disc holding clutches
²Five hydraulic accumulators
²Three planetary gear sets
²Dual Stage Hydraulic oil pump
²Valve body
²Solenoid pack
The TCM is the ªheartº or ªbrainº of the electronic
control system and relies on information from vari-
ous direct and indirect inputs (sensors, switches, etc.)
to determine driver demand and vehicle operating
conditions. With this information, the TCM can cal-
culate and perform timely and quality shifts through
various output or control devices (solenoid pack,
transmission control relay, etc.).
21 - 178 AUTOMATIC TRANSMISSION - 545RFEWJ

INSTALLATION
(1) Place the floor shifter lever in PARK position.
(2) Loosen the adjustment screw on the shift cable.
(3) Verify that the park lock cable adjustment tab
is pulled upward to the unlocked position.
(4) Install wiring harness to the shifter assembly
bracket. Engage any wire connectors removed from
the shifter assembly.
(5) Install the transfer case shift cable to the
shifter assembly bracket. Install clip to hold cable to
the bracket.
(6) Snap the transfer case shift cable, if equipped,
onto the transfer case shift lever pin.
(7) Install the park lock cable into the shifter
assembly bracket and into the shifter BTSI lever.(Re-
fer to 21 - TRANSMISSION/TRANSAXLE/AUTO-
MATIC/SHIFT INTERLOCK MECHANISM -
ADJUSTMENTS)
(8) Install the shift cable to the shifter assembly
bracket. Push cable into the bracket until secure.
(9) Install shifter assembly onto the shifter assem-
bly studs on the floor pan.
(10) Install the nuts to hold the shifter assembly
onto the floor pan. Tighten nuts to 28 N´m (250
in.lbs.).
(11) Snap the shift cable onto the shift lever pin.
(12) Verify that the shift lever is in the PARK posi-
tion.
(13) Tighten the adjustment screw to 7 N´m (65
in.lbs.).
(14) Place the key in the accessory position.
(15) Push downward on the park lock cable adjust-
ment tab to lock the adjustment.
(16) Verify correct shifter, park lock, and BTSI
operation.
(17) Install any console parts removed for access to
shift lever assembly and shift cables. (Refer to 23 -
BODY/INTERIOR/FLOOR CONSOLE - INSTALLA-
TION)
SOLENOID SWITCH VALVE
DESCRIPTION
The Solenoid Switch Valve (SSV) is located in the
valve body and controls the direction of the transmis-
sion fluid when the L/R-TCC solenoid is energized.
OPERATION
The Solenoid Switch Valve controls line pressure
from the LR-TCC solenoid. In 1st gear, the SSV will
be in the downshifted position, thus directing fluid to
the L/R clutch circuit. In 2nd, 3rd, 4th,and 5th gears,
the solenoid switch valve will be in the upshifted
position and directs the fluid into the torque con-
verter clutch (TCC) circuit.When shifting into 1st gear, a special hydraulic
sequence is performed to ensure SSV movement into
the downshifted position. The L/R pressure switch is
monitored to confirm SSV movement. If the move-
ment is not confirmed (the L/R pressure switch does
not close), 2nd gear is substituted for 1st. A DTC will
be set after three unsuccessful attempts are made to
get into 1st gear in one given key start.
SOLENOIDS
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.
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 263
SHIFT MECHANISM (Continued)

TRANSMISSION SOLENOID/
TRS ASSEMBLY
DESCRIPTION
The transmission solenoid/TRS assembly is inter-
nal to the transmission and mounted on the valve
body assembly (Fig. 118). The assembly consists of
six solenoids that control hydraulic pressure to the
six friction elements (transmission clutches), and the
torque converter clutch. The pressure control sole-
noid is located on the side of the solenoid/TRS assem-
bly. The solenoid/TRS assembly also contains five
pressure switches that feed information to the TCM.
OPERATION
SOLENOIDS
Solenoids are used to control the L/R, 2C, 4C, OD,
and UD friction elements. The reverse clutch is con-
trolled by line pressure and the position of the man-
ual valve in the valve body. All the solenoids are
contained within the Solenoid and Pressure Switch
Assembly. The solenoid and pressure switch assembly
contains one additional solenoid, Multi-Select (MS),
which serves primarily to provide 2nd and 3rd gear
limp-in operation.The solenoids receive electrical power from the
Transmission Control Relay through a single wire.
The TCM energizes or operates the solenoids individ-
ually by grounding the return wire of the solenoid as
necessary. When a solenoid is energized, the solenoid
valve shifts, and a fluid passage is opened or closed
(vented or applied), depending on its default operat-
ing state. The result is an apply or release of a fric-
tional element.
The MS and UD solenoids are normally applied to
allow transmission limp-in in the event of an electri-
cal failure.
The continuity of the solenoids and circuits are
periodically tested. Each solenoid is turned on or off
depending on its current state. An inductive spike
should be detected by the TCM during this test. If no
spike is detected, the circuit is tested again to verify
the failure. In addition to the periodic testing, the
solenoid circuits are tested if a speed ratio or pres-
sure switch error occurs.
PRESSURE SWITCHES
The TCM relies on five pressure switches to moni-
tor fluid pressure in the L/R, 2C, 4C, UD, and OD
hydraulic circuits. The primary purpose of these
switches is to help the TCM detect when clutch cir-
cuit hydraulic failures occur. The switches close at 23
psi and open at 11 psi, and simply indicate whether
or not pressure exists. The switches are continuously
monitored by the TCM for the correct states (open or
closed) in each gear as shown in the following chart:
GEAR L/R 2C 4C UD OD
ROP OP OP OP OP
P/NCL OP OP OP OP
1STCL* OP OP CL OP
2NDOP CL OP CL OP
2ND
PRIMEOP OP CL CL OP
DOP OP OP CL CL
4THOP OP CL OP CL
5THOP CL OP OP CL
*L/R is closed if output speed is below 100 rpm in
Drive and Manual 2. L/R is open in Manual 1.
A Diagnostic Trouble Code (DTC) will set if the
TCM senses any switch open or closed at the wrong
time in a given gear.
Fig. 118 Transmission Solenoid/TRS Assembly
1 - PRESSURE CONTROL SOLENOID
2 - TRANSMISSION RANGE SELECTOR PLATE
3 - 23-WAY CONNECTOR
4 - SOLENOID PACK
5 - TRANSMISSION RANGE SENSOR
6 - VALVE BODY
WJAUTOMATIC TRANSMISSION - 545RFE 21 - 271

leak area. If the hose cannot be positioned without
being held, have someone help do the water test.
Some water leaks must be tested for a considerable
length of time to become apparent. When a leak
appears, find the highest point of the water track or
drop. The highest point usually will show the point of
entry. After leak point has been found, repair the
leak and water test to verify that the leak has
stopped.
Locating the entry point of water that is leaking
into a cavity between panels can be difficult. The
trapped water may splash or run from the cavity,
often at a distance from the entry point. Most water
leaks of this type become apparent after accelerating,
stopping, turning, or when on an incline.
MIRROR INSPECTION METHOD
When a leak point area is visually obstructed, use
a suitable mirror to gain visual access. A mirror can
also be used to deflect light to a limited-access area
to assist in locating a leak point.
BRIGHT LIGHT LEAK TEST METHOD
Some water leaks in the luggage compartment can
be detected without water testing. Position the vehi-
cle in a brightly lit area. From inside the darkened
luggage compartment inspect around seals and body
seams. If necessary, have a helper direct a drop light
over the suspected leak areas around the luggage
compartment. If light is visible through a normally
sealed location, water could enter through the open-
ing.
PRESSURIZED LEAK TEST METHOD
When a water leak into the passenger compart-
ment cannot be detected by water testing, pressurize
the passenger compartment and soap test exterior of
the vehicle. To pressurize the passenger compart-
ment, close all doors and windows, start engine, and
set heater control to high blower in HEAT position. If
engine can not be started, connect a charger to the
battery to ensure adequate voltage to the blower.
With interior pressurized, apply dish detergent solu-
tion to suspected leak area on the exterior of the
vehicle. Apply detergent solution with spray device or
soft bristle brush. If soap bubbles occur at a body
seam, joint, seal or gasket, the leak entry point could
be at that location.
WIND NOISE
Wind noise is the result of most air leaks. Air leaks
can be caused by poor sealing, improper body compo-
nent alignment, body seam porosity, or missing plugs
in the engine compartment or door hinge pillar areas.
All body sealing points should be airtight in normal
driving conditions. Moving sealing surfaces will notalways seal airtight under all conditions. At times,
side glass or door seals will allow wind noise to be
noticed in the passenger compartment during high
cross winds. Over compensating on door or glass
adjustments to stop wind noise that occurs under
severe conditions can cause premature seal wear and
excessive closing or latching effort. After a repair pro-
cedure has been performed, test vehicle to verify
noise has stopped before returning vehicle to use.
Wind noise can also be caused by improperly fitted
exterior moldings or body ornamentation. Loose
moldings can flutter, creating a buzzing or chattering
noise. An open cavity or protruding edge can create a
whistling or howling noise. Inspect the exterior of the
vehicle to verify that these conditions do not exist.
VISUAL INSPECTION BEFORE TESTS
Verify that floor and body plugs are in place and
body components are aligned and sealed. If compo-
nent alignment or sealing is necessary, refer to the
appropriate section of this group for proper proce-
dures.
ROAD TESTING WIND NOISE
(1) Drive the vehicle to verify the general location
of the wind noise.
(2) Apply 50 mm (2 in.) masking tape in 150 mm
(6 in.) lengths along weatherstrips, weld seams or
moldings. After each length is applied, drive the vehi-
cle. If noise goes away after a piece of tape is applied,
remove tape, locate, and repair defect.
POSSIBLE CAUSE OF WIND NOISE
²Moldings standing away from body surface can
catch wind and whistle.
²Gaps in sealed areas behind overhanging body
flanges can cause wind-rushing sounds.
²Misaligned movable components.
²Missing or improperly installed plugs in pillars.
²Weld burn through holes.
STANDARD PROCEDURE
STANDARD PROCEDURE - BODY LUBRICATION
All mechanisms and linkages should be lubricated
when necessary. This will maintain ease of operation
and provide protection against rust and excessive
wear. The weatherstrip seals should be lubricated to
prolong their life as well as to improve door sealing.
All applicable exterior and interior vehicle operat-
ing mechanisms should be inspected and cleaned.
Pivot/sliding contact areas on the mechanisms should
then be lubricated.
(1) When necessary, lubricate the operating mech-
anisms with the specified lubricants.
23 - 2 BODYWJ
BODY (Continued)

INSTALLATION
WARNING: REVIEW ALL WARNINGS AND CAU-
TIONS IN THIS GROUP BEFORE PRECEDING WITH
INSTALLATION.
CAUTION: Open a window before installing wind-
shield. This will avoid pressurizing the passenger
compartment. If a door or liftgate is slammed before
urethane is cured, water leaks can result.
The windshield fence should be cleaned of old ure-
thane bonding material. Support spacers should be
cleaned and properly installed on weld studs or
repair screws at bottom of windshield opening.
(1)
Place replacement windshield into windshield
opening. Position glass in the center of the opening
against the support spacers. Mark the glass at the sup-
port spacers with a grease pencil or masking tape and
ink pen to use as a reference for installation. Remove
replacement windshield from windshield opening (Fig. 6).
(2) Position the windshield inside up on a suitable
work surface with two padded, wood 10 cm by 10 cm
by 50 cm (4 in. by 4 in. by 20 in.) blocks, placed par-
allel 75 cm (2.5 ft.) apart (Fig. 7).
(3) Clean inside of windshield with Mopar Glass
Cleaner and lint-free cloth.
(4) Apply clear glass primer 25 mm (1 in.) wide
around edge of windshield. Wipe with clean/dry lint-
free cloth.
(5)
Apply black-out primer 15 mm (.75 in.) wide on
top and sides of windshield and 25 mm (1 in.) on bottom
of windshield. Allow at least three minutes drying time.
(6) Position windshield spacers on lower fence
above support spacers at the edge of the windshield
opening (Fig. 4).
(7)
Apply a 10 mm (0.4 in.) bead of urethane around
perimeter of windshield along the inside of the mold-
ings. Apply two beads along the bottom edge.
(8) Install upper molding onto windshield.
(9) Apply fence primer around the perimeter of the
windshield opening fence. Allow at least 18 minutes
drying time.
(10) With aid of a helper, position windshield over
windshield opening. Align reference marks at bottom
of windshield to support spacers.
(11) Slowly lower windshield glass to windshield
opening fence. Guide top molding into proper position
if necessary. Push windshield inward to fence spacers
at bottom and until top molding is flush to roof line.
(12) Clean excess urethane from exterior with
Mopar Super Clean or equivalent.
(13) Install windshield side moldings.
(14) Install cowl cover and wipers.
(15) Install inside rear view mirror.
(16) After urethane has cured, water test wind-
shield to verify repair.
Fig. 6 Center Windshield and Mark at Support Spacers
1 - A-PILLAR
2 - WINDSHIELD
3 - MARKS
4 - SUPPORT SPACER
5 - COWLFig. 7 Work Surface Set up and Molding Installation
1 - WINDSHIELD AND MOULDINGS
2-
URETHANE BEAD AROUND GLASS 7mm (.3 in.) FROM EDGE
3 - BLOCKS
Fig. 5 Cut Urethane Around WindshieldÐTypical
1 - COLD KNIFE
2 - WINDSHIELD
WJSTATIONARY GLASS 23 - 95
WINDSHIELD (Continued)

CONTROL MODULE
REMOVAL
(1) Move the glass panel to the fully closed posi-
tion.
(2) Remove the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - REMOVAL)
(3) Remove the sun visors. (Refer to 23 - BODY/
INTERIOR/SUN VISOR - REMOVAL)
(4) Remove the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOVAL)
(5) Lower headliner as necessary to gain access to
the sunroof express module.
(6) Disconnect the express module wire harness
connectors.
(7) Remove express module screw.
(8) Remove express module from the keyway by
sliding module towards the center of the vehicle.
INSTALLATION
(1) Insert sunroof express module in the keyway
located in the sunroof module and slide the module
outward to lock it into position.
(2) Install the sunroof express module screw.
(3) Connect the wire connectors to the sunroof
express module.
(4) Install the headliner into position.
(5) Install the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - INSTALLA-
TION)
(6) Install the sun visors. (Refer to 23 - BODY/IN-
TERIOR/SUN VISOR - INSTALLATION)
(7) Install the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - INSTALLATION)
(8) Test sunroof operation, adjust if necessary.
(Refer to 23 - BODY/SUNROOF/GLASS PANEL -
ADJUSTMENTS)
DRIVE MOTOR
REMOVAL
CAUTION: The sunroof system is timed from the
factory so that the motor shuts off automatically
when the sunroof window reaches a certain posi-
tion. Extreme care must be taken when removing
the motor, timing may be thrown off causing possi-
ble damage to the sunroof system. Anytime the
motor is removed from the sunroof assembly the
sunroof glass panel must be in the FULLY CLOSED
POSITION or the unit will be out of timing. The drive
motor cannot be reset to the park position after
being removed.CAUTION: The sunroof motor should only be pow-
ered through the vehicle battery and sunroof wire
harness. Applying power to the sunroof motor leads
will cause failure of the control module.
(1) Move glass panel to the fully closed position.
(2) Remove the A-pillar trim. (Refer to 23 - BODY/
INTERIOR/A-PILLAR TRIM - REMOVAL)
(3) Remove the B-pillar upper trim. (Refer to 23 -
BODY/INTERIOR/B-PILLAR UPPER TRIM -
REMOVAL)
(4) Remove the C-pillar trim. (Refer to 23 - BODY/
INTERIOR/C-PILLAR TRIM - REMOVAL)
(5) Remove the D-pillar trim. (Refer to 23 - BODY/
INTERIOR/D-PILLAR TRIM - REMOVAL)
(6) Remove the sunvisors. (Refer to 23 - BODY/IN-
TERIOR/SUN VISOR - REMOVAL)
(7) Remove the overhead console. (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOVAL)
(8) Disconnect the control switch wire connector.
(9) Remove headliner as necessary to gain access
to sunroof drive motor. Refer to Headliner Removal
and Installation for proper procedures.
(10) Disconnect the drive motor wire harness con-
nectors (Fig. 3).
(11) Remove drive motor fasteners and remove
motor from the sunroof housing.
INSTALLATION
(1) Ensure that the window is in the fully closed
position before mounting the motor. If motor fails
with the window in the open position the sunroof
glass panel timing will have to be timed. The new
motor comes in the fully closed position and with a
gage for setting cable timing. (Refer to 23 - BODY/
SUNROOF/GLASS PANEL - ADJUSTMENTS - TIM-
ING)
(2) Place drive motor into position on the sunroof
housing and install fasteners.
Fig. 3 Sunroof Drive Motor and Express Module
1 - EXPRESS MODULE
2 - SCREW
WJSUNROOF 23 - 101

INSTALLATION
NOTE: Sunroof glass must be set in place and
attached as close as possible to flush with the roof
surface. For wind noise reasons, care must be
taken to ensure that the glass is not remounted
either a) Overflush to the roof surface at the front
edge of the glass, or b) Underflush to the roof sur-
face at the rear edge of the glass.
(1) Position glass panel in to opening.
(2) Start the four attaching screws.
(3) Tighten screws.
(4) Verify sunroof operation and alignment. Check
fit and adjust as necessary. (Refer to 23 - BODY/
SUNROOF/GLASS PANEL - ADJUSTMENTS - FIT)
ADJUSTMENTS
ADJUSTMENTS - FIT
(1) Move the sunshade rearward to the open posi-
tion.
(2) Move the sunroof glass panel to the fully closed
position.
(3) Loosen the forward screws on each side enough
to make the front adjustment.
(4) Adjust the front of the sunroof glass panel 1
mm (1/32 inch) below the top surface of the roof
panel.
(5) Tighten the front two screws.
(6) Loosen the rear screws on each side enough to
make the rear adjustment.
(7) Adjust the rear of the sunroof glass panel 1
mm (1/32 inch) above the top surface of the roof
panel.
(8) Tighten the rear two screws.
(9) Check for proper fit. If not OK, repeat glass
panel adjustment.
ADJUSTMENT - TIMING
NOTE: A gage comes with the new motor.
(1) If the glass panel was not in the fully closed
position, when the motor was removed, the sunroof
glass panel needs to be timed, before the new motor
is installed.
(2) Remove sunroof glass panel.
(3) Set gage into the track near the rear of the
opening between the driver slide and the bracket
(Fig. 6).
(4) Move the driver slide forward or aft to get
proper setting.
(5) Repeat the operation on the other side.
(6) Install drive motor.
SUNSHADE
REMOVAL
(1) Open sunroof approximately 50% of the way.
(2) Push sunshade down until tabs clear glass.
(3) Move sunshade forward of glass panel.
(4) Compress the spring loaded plungers holding
the guide blocks in the track.
(5) Slide the sunshade forward while lifting the
front through the opening until the rear guide blocks
are accessible.
CAUTION: Use care not to crease the sunshade
when removing or installing.
(6) Disengage rear guide blocks from track.
INSTALLATION
(1) Install the sunshade from outside of the vehicle
with the sunroof fully open.
(2) Put rear guide blocks into sunshade guide
track.
(3) Push sunshade back and down through the
sunroof opening.
(4) Using a flat blade tool, put front guide blocks
into the sunshade track. By pushing the block
towards the center of the vehicle.
(5) Move the glass panel to approximately halfway
to the fully closed position.
Fig. 6 Sunroof Drive Cable Timing
1 - MOVE DRIVER SLIDE FORWARD/AFT
2 - GAGE
WJSUNROOF 23 - 103
GLASS PANEL (Continued)

VACUUM RESERVOIR
DESCRIPTION.........................34
OPERATION...........................34
REMOVAL.............................35
INSTALLATION.........................35EVAPORATOR TEMPERATURE SENSOR
DESCRIPTION.........................35
OPERATION...........................35
REMOVAL.............................35
INSTALLATION.........................35
CONTROLS
DIAGNOSIS AND TESTING - VACUUM SYSTEM
Vacuum control is used to operate the mode doors
in the standard equipment manual temperature con-
trol system HVAC housing. Testing of the A/C Heater
mode control switch operation will determine if the
vacuum and electrical controls are functioning. How-
ever, it is possible that a vacuum control system that
operates perfectly at engine idle (high engine vac-
uum) may not function properly at high engine
speeds or loads (low engine vacuum). This can be
caused by leaks in the vacuum system, or a faulty
vacuum check valve.
A vacuum system test will help to identify the
source of poor vacuum system performance or vac-
uum system leaks. Before starting this test, stop the
engine and make certain that the problem isn't a dis-
connected vacuum supply tube at the engine intake
manifold vacuum tap or the vacuum reservoir.
Use an adjustable vacuum test set (Special Tool
C-3707-B) and a suitable vacuum pump to test the
HVAC vacuum control system. With a finger placed
over the end of the vacuum test hose probe (Fig. 1),
adjust the bleed valve on the test set gauge to obtain
a vacuum of exactly 27 kPa (8 in. Hg.). Release and
block the end of the probe several times to verify that
the vacuum reading returns to the exact 27 kPa (8
in. Hg.) setting. Otherwise, a false reading will be
obtained during testing.
VACUUM CHECK VALVES
(1) Remove the vacuum check valve to be tested.
The valves are located in the (black) vacuum supply
tubes at either the engine intake manifold vacuum
tap, or on the bottom of the HVAC unit behind the
passenger front floor duct.
(2) Connect the test set vacuum supply hose to the
A/C Heater control side of the valve. When connected
to this side of the check valve, no vacuum should
pass and the test set gauge should return to the 27
kPa (8 in. Hg.) setting. If OK, go to Step 3. If not OK,
replace the faulty valve.
(3) Connect the test set vacuum supply hose to the
engine vacuum side of the valve. When connected to
this side of the check valve, vacuum should flow
through the valve without restriction. If not OK,
replace the faulty valve.
A/C HEATER CONTROL
(1) Connect the test set vacuum probe to the
HVAC vacuum supply (black) tube in the engine com-
partment. Position the test set gauge so that it can
be viewed from the passenger compartment.
(2) Place the A/C Heater mode control switch knob
in each mode position, one position at a time, and
pause after each selection. The test set gauge should
return to the 27 kPa (8 in. Hg.) setting shortly after
each selection is made. If not OK, a component or
vacuum line in the vacuum circuit of the selected
mode has a leak. See the procedure in Locating Vac-
uum Leaks.
CAUTION: Do not use lubricant on the switch ports
or in the holes in the plug, as lubricant will ruin the
vacuum valve in the switch. A drop of clean water
in the connector plug holes will help the connector
slide onto the switch ports.
Fig. 1 ADJUST VACUUM TEST BLEED VALVE -
TYPICAL
1 - VACUUM PUMP TOOL C-4289
2 - VACUUM TEST SET C-3707
3 - BLEED VALVE
4 - PROBE
24 - 10 CONTROLSWJ