NOTE: If the TCM has been replaced, the ªQuick Learn
Procedureº must be performed. (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/TRANSMIS-
SION CONTROL MODULE - STANDARD PROCEDURE)
BATTERY FEED
A fused, direct battery feed to the TCM is used for
continuous power. This battery voltage is necessary
to retain memory in the TCM. When the battery (B+)
is disconnected, this memory is lost. When the bat-
tery (B+) is restored, this memory loss is detected by
the TCM and a Diagnostic Trouble Code (DTC) is set.
CLUTCH VOLUME INDEXES (CVI)
An important function of the TCM is to monitor
Clutch Volume Indexes (CVI). CVIs represent the vol-
ume of fluid needed to compress a clutch pack.
The TCM monitors gear ratio changes by monitor-
ing the Input and Output Speed Sensors. The Input,
or Turbine Speed Sensor sends an electrical signal to
the TCM that represents input shaft rpm. The Out-
put Speed Sensor provides the TCM with output
shaft speed information.
By comparing the two inputs, the TCM can deter-
mine transmission gear position. This is important to
the CVI calculation because the TCM determines
CVIs by monitoring how long it takes for a gear
change to occur (Fig. 11).
Gear ratios can be determined by using the
DRBIIItScan Tool and reading the Input/Output
Speed Sensor values in the ªMonitorsº display. Gear
ratio can be obtained by dividing the Input Speed
Sensor value by the Output Speed Sensor value.
For example, if the input shaft is rotating at 1000
rpm and the output shaft is rotating at 500 rpm,
then the TCM can determine that the gear ratio is
2:1. In direct drive (3rd gear), the gear ratio changes
to 1:1. The gear ratio changes as clutches are applied
and released. By monitoring the length of time it
takes for the gear ratio to change following a shift
request, the TCM can determine the volume of fluid
used to apply or release a friction element.
The volume of transmission fluid needed to apply
the friction elements are continuously updated for
adaptive controls. As friction material wears, the vol-
ume of fluid need to apply the element increases.
Certain mechanical problems within the input
clutch assembly can cause inadequate or out-of-range
element volumes. Also, defective Input/Output Speed
Sensors and wiring can cause these conditions. The
following chart identifies the appropriate clutch vol-
umes and when they are monitored/updated:
CLUTCH VOLUMES
Clutch When UpdatedProper Clutch
Volume
L/R2-1 or 3-1
downshift45 to 134
2C3-2 kickdown
shift25 to 85
OD 2-3 upshift 30 to 100
4C 3-4 upshift 30 to 85
UD4-3 kickdown
shift30 to 100
SHIFT SCHEDULES
As mentioned earlier, the TCM has programming that
allows it to select a variety of shift schedules. Shift
schedule selection is dependent on the following:
²Shift lever position
²Throttle position
²Engine load
²Fluid temperature
²Software level
As driving conditions change, the TCM appropri-
ately adjusts the shift schedule. Refer to the follow-
ing chart to determine the appropriate operation
expected, depending on driving conditions.
Fig. 11 Example of CVI Calculation
1 - OUTPUT SPEED SENSOR
2 - OUTPUT SHAFT
3 - CLUTCH PACK
4 - SEPARATOR PLATE
5 - FRICTION DISCS
6 - INPUT SHAFT
7 - INPUT SPEED SENSOR
8 - PISTON AND SEAL
8E - 20 ELECTRONIC CONTROL MODULESDR
TRANSMISSION CONTROL MODULE (Continued)
inoperative heated seat switch indicator lamps and
the heated seat elements do not heat, proceed. If the
problem being diagnosed involves inoperative heated
seat switch indicator lamps and the heated seat ele-
ments do heat, go to Step 6. If the problem being
diagnosed involves a heated seat switch indicator
lamp that remains illuminated after the heated seat
has been turned Off, (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/MEMORY
HEATED SEAT/MIRROR MODULE - DIAGNOSIS
AND TESTING).
(2) Disconnect and isolate the battery negative
cable. Remove the heated seat switch and bezel unit
from the instrument panel. Disconnect the heated
seat switch to be tested. Check for continuity
between the ground circuit cavity of the heated seat
switch and a good ground. There should be continu-
ity. If OK, go to Step 3. If not OK, repair the open
ground circuit to ground as required.
(3) Reconnect the battery negative cable. Turn the
park lamps on with the headlamp switch. Rotate the
panel lamps dimmer thumb wheel on the headlamp
switch upward to just before the interior lamps
detent. Check for battery voltage at the fused panel
lamps dimmer circuit cavity of the heated seat
switch. If OK, go to Step 4. If not OK, repair the
open fused panel lamps dimmer switch signal circuit
to the fuse in the Integrated Power Module as
required.
(4) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run) circuit cavity of the heated seat switch.
If OK, go to Step 5. If not OK, repair the open fused
ignition switch output (run) circuit as required.
(5) Check the continuity and resistance values of
the heated seat switch in the Neutral, Low and High
positions as shown in the Heated Seat Switch Conti-
nuity chart. If OK, refer to Step 6. If not OK, replace
the faulty heated seat switch.
HEATED SEAT SWITCH CONTINUITY
Switch PositionContinuity
BetweenResistance
Neutral 4 & 6 2.2 Kilohms
Low 4 & 6 .415 Kilohms
High 4 & 6 33 Ohms(6) Replace the inoperative heated seat switch
with a known good unit and test the operation of the
switch indicator lamps. If OK, discard the faulty
heated seat switch. If not OK, (Refer to 8 - ELEC-
TRICAL/ELECTRONIC CONTROL MODULES/
MEMORY HEATED SEAT/MIRROR MODULE -
DIAGNOSIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the negative battery
cable.
(2) Wait two minutes for the system reserve capac-
itor to discharge before beginning any airbag or
instrument panel service.
(3) Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - REMOV-
AL).
(4) Remove the screws that secure the heated seat
switch bezel to the instrument panel center bezel.
(5) Remove the heated seat switch bezel and both
switches from the instrument panel as a unit.
(6) From the back of the heated seat switch bezel,
gently pry the switch free and push the heated seat
switch out through the front of the bezel.
INSTALLATION
NOTE: When installing the heated seat switches, be
certain they are installed in the proper mounting
holes of the heated seat switch bezel. The heated
seat switches are differentiated by the keyway in
the connector receptacle on the backs of the
switches and keyway on the switch housing (Fig.
4).
(1) From the back of the heated seat switch bezel,
gently push the heated seat switch in through the
front of the bezel.
(2) Position the heated seat switch bezel to the
instrument panel center bezel and install the retain-
ing screws.
(3) Install the center bezel on the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - INSTAL-
LATION).
(4) Connect the battery negative cable.
(5) Verify vehicle and system operation.
DRHEATED SEAT SYSTEM 8G - 9
HEATED SEAT SWITCH (Continued)
NOSIS AND TESTING) or (Refer to 8 - ELECTRI-
CAL/POWER LOCKS/REMOTE KEYLESS ENTRY
MODULE - DIAGNOSIS AND TESTING).
²If the power lock system functions with the RKE
transmitter, but not with one or both power lock
switches, proceed to diagnosis of the door lock
switches. (Refer to 8 - ELECTRICAL/POWER
LOCKS/POWER LOCK SWITCH - DIAGNOSIS AND
TESTING).
²If the driver side power lock switch operates
only the driver side front door power lock motor, but
all other power lock motors operate with the passen-
ger side power lock switch or the RKE transmitter,
use a DRBIIItscan tool and the appropriate diagnos-
tic information to diagnose the Programmable Com-
munications Interface (PCI) data bus.
²If only one power lock motor fails to operate
with both power lock switches and the RKE trans-
mitter, proceed to diagnosis of the power lock motor.
(Refer to 8 - ELECTRICAL/POWER LOCKS/POWER
LOCK MOTOR - DIAGNOSIS AND TESTING).
POWER LOCK SWITCH
DIAGNOSIS AND TESTING - POWER LOCK
SWITCH
The Light-Emitting Diode (LED) illumination lamp
of the power lock switch receives battery current
through a fuse in the Integrated Power Module (IPM)
on a fused ignition switch output (run) circuit. The
power lock switch on the driver side front door trim
panel is integral to the driver door module. (Refer to
8 - ELECTRICAL/POWER LOCKS/DOOR MODULE
- DIAGNOSIS AND TESTING). If the power lock
switch operates, but the LED is inoperative, check
for battery current at the switch with the ignition
switch in the On position. If OK, replace the faulty
switch. Refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.
(1) Disconnect and isolate the battery negative
cable. Remove the power lock switch from the door
trim panel. Disconnect the door wire harness connec-
tor for the power lock switch from the switch connec-
tor receptacle.
(2) Test the power lock switch resistance. See the
Power Lock Switch Test chart to determine if the
resistance is correct for the switch in each switch
position (Fig. 1). If not OK, replace the faulty power
lock switch as required.
REMOVAL
The power lock switch on the driver side front door
trim panel is integral to the driver door module.
(Refer to 8 - ELECTRICAL/POWER LOCKS/DOOR
MODULE - REMOVAL).
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the door trim panel (Refer to 23 -
BODY/DOOR - FRONT/TRIM PANEL - REMOVAL).
(3) Remove the switch from the trim panel bezel.
INSTALLATION
(1) Insert switch to trim panel bezel.
(2) Install door trim panel (Refer to 23 - BODY/
DOOR - FRONT/TRIM PANEL - INSTALLATION).
(3) Connect battery negative cable.
Fig. 1 Power Lock Switch Connector Receptacle
POWER LOCK SWITCH TEST TABLE
SWITCH POSITION RESISTANCE BETWEEN
PINS1&5
NEUTRAL 10 KILOHMS 1%
LOCK 820 OHMS 5%
UNLOCK 330 OHMS 5%
8N - 4 POWER LOCKSDR
POWER LOCKS (Continued)
the Integrated Power Module (IPM) on a fused igni-
tion switch output (run-acc) circuit so that the power
windows will operate whenever the ignition switch is
in the On or Accessory positions. Each two-way,
momentary master passenger power window switch
in the DDM provides battery current and ground to
the individual power window switches on each pas-
senger door so that the power window switch controls
the battery current and ground feeds to its respective
power window motor. The DDM switch for the driver
side front door power window is labeled ªAutoº and
includes an auto-down feature. When this switch is
depressed to a second momentary detent position and
released, the driver door power window is automati-
cally operated through an internal circuit and relay
to its fully lowered position. The Auto-down event is
cancelled if the switch paddle is depressed a second
time in either the Up or Down direction. When the
two position window lockout switch in the DDM is
depressed and latched in the lockout position, the
battery current feed to each of the individual passen-
ger power window switches is interrupted so that the
passenger door power windows can only be operated
from the master switches in the DDM. The window
lockout switch also controls the battery current feed
for the LED in each passenger power window switch
so that the switch will not be illuminated when it is
locked out.
Power Mirror Switches
The DDM power mirror switch circuitry is con-
nected to battery current through a fuse in the IPM
on a fused B(+) circuit so that the power mirrors
remain operational regardless of the ignition switch
position. A rocker type selector switch has three posi-
tions, one to select the right mirror, one to select the
left mirror, and a neutral Off position. After the right
or left mirror is selected, one of four directional but-
tons is depressed to move the selected mirror Up,
Down, Right or Left. The DDM power mirror switch
circuitry controls the battery current and ground
feeds to each of the four (two in each mirror head)
power mirror motors. The Light-Emitting Diode
(LED) in the DDM power mirror switch is connected
to battery current through the power window circuit
breaker in the IPM on a fused ignition switch output
(run-acc) circuit so that the switch directional but-
tons will be illuminated whenever the ignition switch
is in the On or Accessory positions.DIAGNOSIS AND TESTING - DRIVER DOOR
MODULE
The Light-Emitting Diode (LED) illumination
lamps for all of the Driver Door Module (DDM)
power window, power lock, and power mirror
switches receive battery current through the power
window circuit breaker in the Integrated Power Mod-
ule (IPM). If all of the LEDs are inoperative in the
DDM, be certain to diagnose the power window sys-
tem before replacing the switch unit. (Refer to 8 -
ELECTRICAL/POWER WINDOWS - DIAGNOSIS
AND TESTING). If only one LED in the DDM is
inoperative, replace the faulty DDM. If the driver
side front door power window operates in a normal
manner, but the Auto-Down feature is inoperative,
replace the faulty DDM. Refer to the appropriate wir-
ing information. The wiring information includes wir-
ing diagrams, proper wire and connector repair
procedures, details of wire harness routing and
retention, connector pin-out information and location
views for the various wire harness connectors, splices
and grounds.
(1) Disconnect and isolate the battery negative
cable. Remove the DDM from the door trim panel.
Disconnect the door wire harness connectors for the
DDM from the DDM connector receptacles.
(2) Test the DDM switch continuity. See the Driver
Door Module Switch Tests chart to determine if the
continuity is correct for the suspect switches in each
switch position (Fig. 2) and/or (Fig. 3). If not OK,
replace the faulty DDM as required.
Fig. 2 Driver Door Module Connector C1 Receptacle
8N - 6 POWER LOCKSDR
DRIVER DOOR MODULE (Continued)
POWER MIRROR MOTOR TEST
If the power mirror switch is receiving proper cur-
rent and ground and mirrors do not operate, proceed
with power mirror motor test. Refer to the appropri-
ate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
(1) Remove the power mirror switch (Refer to 8 -
ELECTRICAL/POWER LOCKS/DOOR MODULE -
REMOVAL).
(2) Disconnect wire harness connector to power
mirror switch (Fig. 1).
(3) Using two jumper wires:
²Connect one to a 12 volt source
²Connect the other to a good body ground
²Refer to the Mirror Motor Test Chart for proper
wire connections at the switch connector
MIRROR MOTOR TEST CHART
12 VOLTS GROUND MIRROR REACTION
SWITCH CONNECTOR RIGHT LEFT
PIN 1 PIN 2 - UP
PIN 6 PIN 2 - LEFT
PIN 2 PIN 1 - DOWN
PIN 2 PIN 6 - RIGHT
PIN 7 PIN 2 UP -
PIN 4 PIN 2 LEFT -
PIN 2 PIN 7 DOWN -
PIN 2 PIN 4 RIGHT -
(4) If results shown in table are not obtained,
check for open or shorted circuit. Replace mirror
assembly as necessary.
AUTOMATIC DAY / NIGHT
MIRROR
DESCRIPTION
The automatic day/night mirror uses a thin layer
of electrochromic material between two pieces of con-
ductive glass to make up the face of the mirror.
When the mirror switch is in the On position, two
photocell sensors are used by the mirror circuitry to
monitor external light levels and adjust the reflec-
tance of the mirror.
OPERATION
The ambient photocell sensor is located on the for-
ward-facing (windshield side) of the rear view mirror
housing, and detects the ambient light levels outside
of the vehicle. The headlamp photocell sensor is
located inside the rear view mirror housing behind
the mirror glass and faces rearward, to detect the
level of the light being received at the rear window
side of the mirror. When the circuitry of the auto-
matic day/night mirror detects that the difference
between the two light levels is too great (the light
level received at the rear of the mirror is much
higher than that at the front of the mirror), it begins
to darken the mirror.
The automatic day/night mirror circuitry also mon-
itors the transmission using an input from the
backup lamp circuit. The mirror circuitry is pro-
grammed to automatically disable its self-dimming
feature whenever it senses that the transmission
backup lamp circuit is energized.
The automatic day/night mirror is a completely
self-contained unit and cannot be repaired. If faulty
or damaged, the entire mirror assembly must be
replaced.
DIAGNOSIS AND TESTING - AUTOMATIC DAY /
NIGHT MIRROR
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
(1) Check the fuse in the Integrated Power Module
(IPM). If OK, go to Step 2. If not OK, repair the
shorted circuit or component as required and replace
the faulty fuse.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the IPM. If
OK, go to Step 3. If not OK, repair the open circuit to
the ignition switch as required.
Fig. 1 POWER MIRROR SWITCH CONNECTOR
8N - 12 POWER MIRRORSDR
POWER MIRRORS (Continued)
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
REMOVAL).
(2) Disconnect power window motor wire connector
from door harness.
(3) Using two jumper wires, connect one to a bat-
tery (+) source and the other to a good ground (-).
(4) Connect the Negative (-) jumper probe to one of
the motor connector terminals.
(5) Momentarily touch the Positive (+) jumper
probe to the other motor connector terminal.
When positive probe is connected the motor should
rotate in one direction to either move window up or
down. If window is all the way up or down the motor
will grunt and the inner door panel will flex when
actuated in that one direction.
(6) Reverse jumper probes at the motor connector
terminals and window should now move in opposite
direction. If window does not move or grunt, replace
the motor.
If window moved completely up or down, reverse
the jumper probes and cycle window to the opposite
position to verify full operation.
If motor grunts and does not move, verify that reg-
ulator is not binding.
WINDOW MOTOR
REMOVAL
The window motor is serviced with the window reg-
ulator (Refer to 23 - BODY/DOOR - FRONT/WINDOW
REGULATOR - REMOVAL) or (Refer to 23 - BODY/
DOORS - REAR/WINDOW REGULATOR - REMOVAL).
WINDOW SWITCH
DIAGNOSIS AND TESTING - WINDOW SWITCH
The Light-Emitting Diode (LED) illumination
lamps for all of the power window and lock switch
and bezel unit switch paddles receive battery current
through the power window circuit breaker in the
junction block. If all of the LEDs are inoperative in
both the power window and lock switch units and the
power windows are inoperative, (Refer to 8 - ELEC-
TRICAL/POWER WINDOWS - DIAGNOSIS AND
TESTING). If the power windows operate, but any or
all of the LEDs are inoperative, the power window
and lock switch units with the inoperative LED(s) is
faulty and must be replaced. For complete circuit dia-
grams, refer to the appropriate wiring information.
The wiring information includes wiring diagrams,
proper wire and connector repair procedures, details
of wire harness routing and retention, connector pin-
out information and location views for the various
wire harness connectors, splices and grounds.(1) Check the fuse in the Integrated Power Module
(IPM) and the circuit breaker located near the park
brake pedal. If OK, go to Step 2. If not OK, replace
the faulty fuse or circuit breaker.
(2) Turn the ignition switch to the On position.
Check for battery voltage at the fuse in the Inte-
grated Power Module (IPM). If OK, turn the ignition
switch to the Off position and go to Step 3. If not OK,
check circuit breaker and repair the circuit to the
ignition switch as required.
(3) Disconnect and isolate the battery negative
cable. Remove the power window switch unit from
the door trim panel (passenger doors). The drivers
door switch is included with the Driver Door Module
(Refer to 8 - ELECTRICAL/POWER LOCKS/DOOR
MODULE - DIAGNOSIS AND TESTING) for service
procedures. Unplug the wire harness connector from
the switch unit.
(4) Test the power window switch continuity. See
the Power Window Switch Continuity charts to deter-
mine if the continuity is correct in the Off, Up and
Down switch positions (Fig. 1). If OK, (Refer to 8 -
ELECTRICAL/POWER WINDOWS - DIAGNOSIS
AND TESTING). If not OK, replace the faulty switch.
POWER WINDOW SWITCH CONTINUITY
CHART
SWITCH POSITION CONTINUITY BETWEEN
NEUTRAL PIN 2 AND 5, PIN 4 AND 1
UP (FRONT
PASSENGER)PIN 6 AND 5
UP (REAR
PASSENGER)PIN 6 AND 1
DOWN (FRONT
PASSENGER)PIN 6 AND 1
DOWN (REAR
PASSENGER)PIN 6 AND 5
Fig. 1 PASSENGER DOOR SWITCH
8N - 22 POWER WINDOWSDR
POWER WINDOWS (Continued)
DESCRIPTION - CIRCUIT FUNCTIONS
All circuits in the diagrams use an alpha/numeric
code to identify the wire and it's function. To identify
which circuit code applies to a system, refer to the
Circuit Identification Code Chart. This chart shows
the main circuits only and does not show the second-
ary codes that may apply to some models.
CIRCUIT IDENTIFICATION CODE CHART
CIRCUIT FUNCTION
A BATTERY FEED
B BRAKE CONTROLS
C CLIMATE CONTROLS
D DIAGNOSTIC CIRCUITS
E DIMMING ILLUMINATION
CIRCUITS
F FUSED CIRCUITS
G MONITORING CIRCUITS
(GAUGES)
H OPEN
I NOT USED
J OPEN
K POWERTRAIN CONTROL
MODULE
L EXTERIOR LIGHTING
M INTERIOR LIGHTING
N NOT USED
O NOT USED
P POWER OPTION (BATTERY
FEED)
Q POWER OPTIONS (IGNITION
FEED)
R PASSIVE RESTRAINT
S SUSPENSION/STEERING
T TRANSMISSION/TRANSAXLE/
TRANSFER CASE
U OPEN
V SPEED CONTROL, WIPER/
WASHER
W OPEN
X AUDIO SYSTEMS
Y OPEN
Z GROUNDS
DESCRIPTION - SECTION IDENTIFICATION AND
INFORMATION
The wiring diagrams are grouped into individual
sections. If a component is most likely found in a par-
ticular group, it will be shown complete (all wires,
connectors, and pins) within that group. For exam-
ple, the Auto Shutdown Relay is most likely to be
found in Group 30, so it is shown there complete. It
can, however, be shown partially in another group if
it contains some associated wiring.
Splice diagrams in Section 8W-70 show the entire
splice and provide references to other sections the
splices serves. Section 8W-70 only contains splice dia-
grams that are not shown in their entirety some-
where else in the wiring diagrams.
Section 8W-80 shows each connector and the cir-
cuits involved with that connector. The connectors
are identified using the name/number on the dia-
gram pages.
WIRING SECTION CHART
GROUP TOPIC
8W-01 thru
8W-09General information and Diagram
Overview
8W-10 thru
8W-19Main Sources of Power and
Vehicle Grounding
8W-20 thru
8W-29Starting and Charging
8W-30 thru
8W-39Powertrain/Drivetrain Systems
8W-40 thru
8W-49Body Electrical items and A/C
8W-50 thru
8W-59Exterior Lighting, Wipers and
Trailer Tow
8W-60 thru
8W-69Power Accessories
8W-70 Splice Information
8W-80 Connector Pin Outs
8W-91 Connector, Ground and Splice
Locations
8W - 01 - 6 8W-01 WIRING DIAGRAM INFORMATIONDR
WIRING DIAGRAM INFORMATION (Continued)
(3) Start the engine and hold the idle at 1,000 rpm
with the compressor clutch engaged.
(4) The engine should be at operating temperature.
The doors and windows must be closed.
(5) Insert a thermometer in the driver side center
A/C (panel) outlet. Operate the engine for five min-
utes.
(6) The compressor clutch may cycle, depending
upon the ambient temperature and humidity.
(7) With the compressor clutch engaged, record the
discharge air temperature and the compressor dis-
charge pressure.(8) Compare the discharge air temperature to the
Performance Temperature and Pressure chart. If the
discharge air temperature is high, (Refer to 24 -
HEATING & AIR CONDITIONING/PLUMBING -
DIAGNOSIS AND TESTING - REFRIGERANT SYS-
TEM LEAKS) and (Refer to 24 - HEATING & AIR
CONDITIONING/PLUMBING - SPECIFICATIONS -
CHARGE CAPACITY).
Performance Temperature and Pressure
Ambient Air
Temperature21É C
(70É F)27É C
(80É F)32É C
(90É F)38É C
(100É F)43É C
(110É F)
Air Temperature at
Center Panel Outlet7É C
(45É F)7É C
(45É F)13É C
(55É F)13É C
(55É F)18É C
(64É F)
Compressor Inlet
Pressure at Service
Port (low Side)138 to 207 kPa
(20 to 30 psi)172 to 241
kPa
(25 to 35 psi)207 to 276
kPa
(30 to 40 psi)241 to 310
kPa
(35 to 45 psi)276 to 345 kPa
(40 to 50 psi)
Condensor Out
Pressuree at Service
Port (High Side)1034 to 1724
kPa
(150 to 250
psi)1379 to 2068
kPa
(200 to 300
psi)1724 to 2413
kPa
(250 to 350
psi)1999 to 2689
kPa
(290 to 390
psi)2413 to 2965
kPa
(350 to 430 psi)
(9) Compare the compressor discharge pressure to
the Performance Temperature and Pressure chart. Ifthe compressor discharge pressure is high, see the
Pressure Diagnosis chart.
Pressure Diagnosis
Condition Possible Causes Correction
Constant compressor
engagement and warm air
from passenger vents.1. Low refrigerant system
charge.1. See Plumbing/Diagnosis and Testing -
Refrigerant System Leaks in this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
Equal pressures, but the
compressor clutch does not
engage.1. No refrigerant in the
refrigerant system.1. See Plumbing/Diagnosis and Testing -
Refrigerant System Leaks in this group. Test the
refrigerant system for leaks. Repair, evacuate and
charge the refrigerant system, if required.
2. Faulty fuse. 2. Check the fuses in the Power Distribution
Center and the junction block. Repair the shorted
circuit or component and replace the fuses, if
required.
3. Faulty a/c compressor
clutch coil.3. See A/C Compressor/Diagnosis and Testing -
Compressor Clutch Coil in this group. Test the
compressor clutch coil and replace, if required.
DRHEATING & AIR CONDITIONING 24 - 3
HEATING & AIR CONDITIONING (Continued)