Page 571 of 1500
FLOOR, SEAT AND ROOF
CONFIGURATION DIAGRAMS80-22
D-26 (20-Y) SRS-ECU (FLOOR HARNESS)
D-27 (20-Y) SRS-ECU (FLOOR HARNESS)
D-28 (5-B) SEAT BELT BUCKLE SWITCH
(DRIVER’S SIDE)
D-30 (2) WHEEL SPEED SENSOR (REAR:
RH)
D-31 (2) WHEEL SPEED SENSOR (REAR:
LH)
D-32 (2-R) SIDE AIR BAG MODULE (SQUIB)
(RH)
D-33 (2-B) SEAT BELT PRETENSIONER (RH)
D-34 (3) FRONT DOOR SWITCH (RH)D-35 (2) SIDE IMPACT SENSOR (RH)
D-36 (10) FLOOR WIRING HARNESS AND
REAR DOOR WIRING HARNESS
(RH) COMBINATION
D-38 (8) POWER SEAT (MEMORY) (RH)
D-39 (2) POWER SEAT ASSEMBLY (LH)
D-39-1 (5-W) FRONT HEIGHT MOTOR
D-39-2 (5-B) REAR HEIGHT MOTOR
D-39-3 (4) SEAT SLIDE MOTOR
D-39-4 (8) SEAT ADJUST SWITCH (LH)
D-40 (1-B) CAPACITOR
Page 589 of 1500

CENTRALISED JUNCTION
CIRCUIT DIAGRAMS90-12
CENTRALISED JUNCTIONM1901000301013
FUSIBLE LINK AND FUSE
ENGINE COMPARTMENT
NO. POWER SUPPLY
CIRCUITNAME RATED
CAPACITY (A)HOUSING
COLOURLOAD CIRCUIT
1 Battery/Alternator
(Fusible link No.27)Fusible
link80 Black Fuse Nos.5, 6, 9 and 10 (in junction
block) circuit
2 50 Blue Radiator fan motor
3 30 Pink ABS-ECU and ABS/TCL-ECU (motor
power supply)
4 40 Green Ignition switch circuit
5 40 Green Fuse Nos.3 and 4 (in junction block
circuit), front power window regulator
motor, power seat assembly, power
window main switch and rear power
window regulator motor
6 Fuse 15 Blue Fog lamp and fog lamp relay
720Yellow
8 15 Red Horn (High), horn (Low) and horn
relay
9 20 Yellow Camshaft position sensor, crankshaft
position sensor, engine oil control
valve, evaporative emission purge
solenoid, evaporative emission
ventilation solenoid, heated oxygen
sensor,ETACS-ECU, injector, mass
airflow sensor, MPI relay, Engine
ECU, A/T ECU, throttle actuator
control motor relay and fan control
relay
10 10 Red A/C compressor assembly and
A/C-ECU
11 15 Blue ABS-ECU, ABS/TCL-ECU,
high-mounted stoplamp, Engine ECU
and rear combination lamp
12
13 7.5 Brown
Alternator
14 10 Red ETACS-ECU, Hazard lamps
15 20 Yellow A/T control solenoid valve and Engine
ECU
16 Front-ECU
(Headlamp relay:
High)15 Blue Headlamp (RH) and headlamp (High:
RH)
17 15 Blue Headlamp (LH) and headlamp (High:
LH)
18 Front-ECU (Field
effect transistor for
headlamp: Low)10 Red Headlamp (RH) and headlamp (Low:
RH)
Page 590 of 1500

CENTRALISED JUNCTION
CIRCUIT DIAGRAMS90-13
19 Front-ECU (Field
effect transistor for
headlamp: Low)Fuse 10 Red Headlamp (LH) and headlamp (Low:
LH)
20 Front-ECU (Taillamp
relay)7.5 Brown A/C-ECU, A/T selector lever position
illumination lamp, combination meter,
fog lamp switch, headlamp (RH),
glove box lamp, hazard warning lamp
switch, multi-center display unit,
radio, CD player, rear combination
lamp (RH), rheostat and TCL switch
21 7.5 Brown Headlamp (LH), license plate lamp
and rear combination lamp (LH)
22 Battery/Alternator
(Fusible link No.27)15 Blue A/C-ECU, column switch,
combination meter, ETACS-ECU,
front-ECU, key reminder switch, multi-
center display unit, radio, CD player,
and vanity mirror lamp
23 Ignition switch (ACC) 10 Red A/C-ECU, accessory socket relay,
ETACS-ECU, multi-center display
unit, radio, CD player.
24 Battery/Alternator
(Fusible link No.27)15 Blue Fuel pump module
25 Ignition switch (ACC) 30 Green Front-ECU and windshield wiper
motor
26 Battery/Alternator
(Fusible link No.27)Fusible
link20 Light blue Anti-lock braking system(solenoid
valve)
27
Alternator120
Battery, front-ECU, fusible link Nos.1,
2, 3, 4, 5 and 26 and fuse Nos.6, 7, 8,
9, 10, 11, 13, 14, 15, 22 and 24 (in
relay box) NO. POWER SUPPLY
CIRCUITNAME RATED
CAPACITY (A)HOUSING
COLOURLOAD CIRCUIT
Page 592 of 1500

CENTRALISED JUNCTION
CIRCUIT DIAGRAMS90-15
NO. POWER SUPPLY
CIRCUITNAME RATED
CAPACITY (A)HOUSING
COLOURLOAD CIRCUIT
1 Fusible link No.1 Fuse 30 Green Rear window demister
2 30 Green Blower motor and resistor
3
4
5 15 Blue Accessory socket
6 15 Blue Data link connector and ETACS-ECU
7 Ignition switch (ACC) 15 Blue ETACS-ECU
8
9 Ignition switch (IG2) 7.5 Brown Sunroof assembly
10 Ignition switch (ACC) 7.5 Brown Remote controlled mirror
11
12
13 Ignition switch (IG1) 7.5 Brown Fuel pump relay and Engine ECU
14 Ignition switch (ACC) 20 Yellow Windscreen wiper
15 Fusible link No.1
(Fuse No.5 in junction
block)7.5 Brown Remote controlled mirror
16 Ignition switch (IG2) 7.5 Brown A/C compressor clutch relay,
A/C-ECU, blower relay, condenser
fan motor, fan control relay,
front-ECU, outside/inside air selection
damper control motor and rear
window defogger relay
17 Ignition switch (IG1)
18 7.5 Brown A/T control relay, input shaft speed
sensor, output shaft speed sensor,
Engine ECU, rear combination lamp
and SRS-ECU
19 7.5 Brown ABS-ECU, ABS/TCL-ECU, column
switch, combination meter,
ETACS-ECU, multi-center display unit
and SRS-ECU
20 10 Red Ignition coil
21
22
23 Fusible link No.5 20 Yellow Sunroof assembly
24
Page 594 of 1500
CENTRALISED JUNCTION
CIRCUIT DIAGRAMS90-17
CENTRALISED RELAY
NOTE: The triangle mark on the relay housing should face that on the relay box.CONNECTOR NO. NAME CONNECTOR NO. NAME
A-05X Fog lamp relay A-16X
A-06X Horn relay B-11X
A-07XB-12X
A-08XB-13X
A-09XB-14X
A-10X Fan control relay B-15X
A-11X Front-ECU B-16X A/T control relay
A-12X Front-ECU B-17X
MPI relay
A-15X
B-18X A/C compressor clutch relay
Page 702 of 1500

HEATER, AIR CONDITIONING AND VENTILATION55-1
GROUP 55
HEATER, AIR
CONDITIONING AND
VENTILATION
CONTENTS
GENERAL DESCRIPTION. . . . . . . . .55-3
AUTO A/C DIAGNOSIS . . . . . . . . . . .55-5
INTRODUCTION. . . . . . . . . . . . . . . . . . . . . 55-5
AUTOMATIC AIR CONDITIONING
TROUBLESHOOTING STRATEGY . . . . . . 55-5
DIAGNOSTIC FUNCTION . . . . . . . . . . . . . 55-5
DIAGNOSTIC TROUBLE CODE CHART . 55-9
DIAGNOSTIC TROUBLE CODE
PROCEDURES . . . . . . . . . . . . . . . . . . . . . . 55-10
SYMPTOM CHART . . . . . . . . . . . . . . . . . . 55-68
SYMPTOM PROCEDURES . . . . . . . . . . . . 55-69
DATA LIST REFERENCE TABLE . . . . . . . 55-133
ACTUATOR TEST REFERENCE . . . . . . . . 55-136
CHECK AT A/C-ECU TERMINAL . . . . . . . . 55-137
SPECIAL TOOLS . . . . . . . . . . . . . . . .55-139
ON-VEHICLE SERVICE . . . . . . . . . . .55-141
REFRIGERANT LEVEL TEST . . . . . . . . . . 55-141
A/C COMPRESSOR CLUTCH TEST . . . . . 55-141
SIMPLE INSPECTION OF THE A/C
PRESSURE SENSOR . . . . . . . . . . . . . . . . 55-141
COMPRESSOR DRIVE BELT
ADJUSTMENT . . . . . . . . . . . . . . . . . . . . . . 55-142
CHARGING . . . . . . . . . . . . . . . . . . . . . . . . . 55-142
PERFORMANCE TEST . . . . . . . . . . . . . . . 55-143
REFRIGERANT LEAK INSPECTION
PROCEDURE . . . . . . . . . . . . . . . . . . . . . . . 55-144A/C NOISE TEST . . . . . . . . . . . . . . . . . . . . 55-146
POWER RELAY CHECK . . . . . . . . . . . . . . . 55-148
IDLE-UP OPERATION CHECK . . . . . . . . . . 55-149
HEATER CONTROL ASSEMBLY AND
A/C SWITCH . . . . . . . . . . . . . . . . . . . .55-150
REMOVAL AND INSTALLATION . . . . . . . . 55-150
HEATER UNIT, HEATER CORE,
BLOWER ASSEMBLY AND
EVAPORATOR UNIT . . . . . . . . . . . . .55-151
REMOVAL AND INSTALLATION . . . . . . . . 55-151
REMOVAL AND INSTALLATION . . . . . . . . 55-153
DISASSEMBLY AND ASSEMBLY . . . . . . . 55-154
INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 55-155
BLOWER ASSEMBLY DISASSEMBLY
AND ASSEMBLY . . . . . . . . . . . . . . . . . . . . . 55-156
MOTORS AND TRANSISTOR . . . . . .55-157
REMOVAL AND INSTALLATION . . . . . . . . 55-157
INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 55-158
SENSORS . . . . . . . . . . . . . . . . . . . . . .55-160
REMOVAL AND INSTALLATION . . . . . . . . 55-160
INSPECTION. . . . . . . . . . . . . . . . . . . . . . . . 55-161
Continued on next page
Page 705 of 1500

GENERAL DESCRIPTION
HEATER, AIR CONDITIONING AND VENTILATION55-4
OPERATION
.
CONDENSER FAN AND RADIATOR FAN
CONTROL
The ECU judges the required revolution speed of
radiator fan motor and condenser fan motor using
the input signals transmitted from A/C switch, output
shaft speed sensor and engine coolant temperature
sensor. The ECU activates the fan control relays to
drive the radiator fan motor and condenser fan
motor.
.
COMPRESSOR CONTROL
When operating the air conditioning switch
The air thermo sensor, which senses the temper-
ature of the air flowing out of the evaporator,
deactivates the compressor at 3
C (37.4F) or
below.
The dual pressure switch turns OFF when the
refrigerant pressure becomes excessively high or
low, thus protecting the compressor circuit (See
Table below).
When the air thermo sensor is activated, and the
ignition switch, blower switch, and air condition-
ing switch are ON, the A/C compressor clutch
relay is energized.
When operating the mode selection dial
The air conditioning will work when the mode
selection dial is set to the "Defroster" or
"Defroster/foot" position, or the temperature con-
trol dial is set to the "MAX A/C" position. In other
dial positions, when the air conditioning switch is
turned on, the air conditioning will work.
A/C Compressor Clutch Relay ON Conditions
Ignition switch (IG2) ONNOTE: A/C compressor clutch relay is
de-energized when any one switch, sensor
or control unit shown on the left turns off.
NOTE: The components marked by
*
communicate with the ECU. If the air thermo
sensor detects a temperature of 3
C
(37.4
F), the A/C-ECU will turn off the A/C
compressor clutch relay. Blower switch ON
Air conditioning switch, mode selection dial
defroster, defroster/foot position or temperature
control MAX A/CON
Air thermo sensor*
Pressure detected
by A/C pressure
sensor2940 kPa or less (If the
refrigerant pressure exceeds
2940 kPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 2350 kPa or less.)ON
190 kPa or more (If the
refrigerant pressure falls short
of 190 kPa, A/C compressor
clutch relay is not ON
condition until the refrigerant
pressure has been measured
up to 220 kPa or more.)
A/C compressor clutch relay driving transistor (within
ecu)ON
Page 711 of 1500

AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-10
DIAGNOSTIC TROUBLE CODE PROCEDURES
DTC B1001, B1002: Interior Temperature Sensor System.
DTC SET CONDITION
DTC B1001 is set if there is a short circuit in the
interior temperature sensor input circuit.
DTC B1002 is set if there is a defective connector
connection, or if there is an open circuit in the
harness.
.
TECHNICAL DESCRIPTION (COMMENT)
Current trouble
The A/C-ECU, the interior air temperature sensor,
or connector(s) or wiring between the two may be
defective.Past trouble
If DTC B1001 or B1002 is stored as a past trou-
ble, carry out diagnosis with particular emphasis
on wiring and connector(s) between the A/C-ECU
and the interior air temperature sensor. If the con-
nectors and wiring are normal, and obviously the
ECU is the cause of the trouble, replace the ECU.
If in doubt, do not replace the ECU.
.
TROUBLESHOOTING HINT
Malfunction of connector.
Malfunction of the harness.
Malfunction of the interior temperature sensor.
Malfunction of the A/C-ECU.
Refer to component locations GROUP-70
Refer to configuration diagrams GROUP-80
Refer to circuit diagrams GROUP-90
DIAGNOSIS
Required Special Tool:
: Diagnostic Tool (MUT-III Sub Assembly)
MB991824: Vehicle Communication Interface (V.C.I.)
MB991827: MUT-III USB Cable
MB991910: MUT-III Main Harness A (Vehicles with CAN
communication system)