Page 820 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-119
STEP 12. Check the wiring harness between defogger
relay connector C-201 (terminal 4) and choke coil
connector D-11 (terminal 1).
NOTE: Also check junction block connector C-204 for loose,
corroded, or damaged terminals, or terminals pushed back in
the connector. If junction block connector C-204 is damaged,
repair or replace the connector as described in GROUP 00E,
Harness Connector Inspection P.00E-2.
Q: Is the wiring harness between defogger relay connector
C-201 (terminal 4) and choke coil connector D-11
(terminal 1) in good condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair or replace the wiring harness. Refer to
GROUP 00E, Harness Connector Inspection
P.00E-2. Check that the defogger system works
normally.
STEP 13. Check choke coil connector D-11 for loose,
corroded or damaged terminals, or terminals pushed back
in the connector.
Q: Is choke coil connector D-11 in good condition?
YES : Go to Step 14.
NO : Repair or replace the connector. Refer to GROUP
00E, Harness Connector Inspection P.00E-2. Check
that the defogger system works normally.
Page 825 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-124
NOTE: Also check junction block connectors C-211 and C-215
for loose, corroded, or damaged terminals, or terminals pushed
back in the connector. If junction block connector C-211 or
C-215 is damaged, repair or replace the connector as
described in GROUP 00E, Harness Connector Inspection
P.00E-2.
Q: Is the wiring harness between A/C-ECU connector C-16
(terminal 28) and the ignition switch (IG2) in good
condition?
YES : It can be assumed that this malfunction is intermittent.
Refer to GROUP 00, How to Use
Troubleshooting/Inspection Service Points
How to
Cope with Intermittent Malfunctions P.00-14.
NO : Repair the wiring harness. Check that the air
conditioning works normally.
STEP 4. Measure the voltage at A/C-ECU connector C-16.
(1) Disconnect A/C-ECU connector C-16 and measure the
voltage at the harness side.
(2) Turn the ignition switch to the "ACC" position.
(3) Measure the voltage between terminal 36 and ground.
The measured value should be approximately 12 volts
(battery positive voltage).
Q: Is the measured voltage approx. 12 volts?
YES : Go to Step 6.
NO : Go to Step 5.
Page 830 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-129
DIAGNOSIS
Required Special Tools:
: Scan 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)
STEP 1. Check the defogger and outside/inside air
selection damper control motor operation.
Q: Do the defogger and outside/inside air selection damper
control motor work normally?
YES : Go to Step 2.
NO : Refer to GROUP 55, AUTO A/C Diagnosis, P.55-70.
STEP 2. Using scan tool , read diagnostic trouble code.
To prevent damage to scan tool , always turn the ignition
switch to the "LOCK" (OFF) position before connecting or
disconnecting scan tool .
Check if an A/C-ECU DTC is set.
1. Connect scan tool to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Check if the DTC is set.
4. Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the DTC set?
YES : Refer to P.55-9.
NO : Go to Step 3.
Page 831 of 1500
AUTO A/C DIAGNOSIS
HEATER, AIR CONDITIONING AND VENTILATION55-130
STEP 3. Using scan tool , check data list item 67: Photo
sensor.
(1) Connect scan tool to the data link connector.
(2) Start the engine.
(3) Set scan tool to the data reading mode for item 67: Photo
sensor.
Check that the display on the scan tool changes when
the photo sensor is covered with hands.
(4) Turn the ignition switch to the "LOCK" (OFF) position.
Q: Is the sensor within the specified range?
YES : Go to Step 7.
NO : Go to Step 4.
Page 852 of 1500
HEATER UNIT, HEATER CORE, BLOWER ASSEMBLY AND EVAPORATOR UNIT
HEATER, AIR CONDITIONING AND VENTILATION55-151
HEATER UNIT, HEATER CORE, BLOWER ASSEMBLY AND
EVAPORATOR UNIT
REMOVAL AND INSTALLATIONM1552021400012
Before removing the front seat assembly, refer to GROUP 52B, Service Precautions
P.52B-16 and Air Bag Module and Clock Spring P.52B-237.
Pre-removal and Post-installation Operation
Refrigerant draining and Refilling (Refer to Charging and
Discharging P.55-142).
Engine coolant Draining and Refilling (Refer to GROUP
00, Engine coolant P.00-47).
Instrument Panel Removal and Installation (Refer to
GROUP 52A, Instrument Panel P.52A-4).
Steering Column Shaft Assembly Removal and Installa-
tion (Refer to GROUP 37A, Steering ShaftP.37-25).
Floor Console Removal and Installation (Refer to GROUP
52A, Floor Console P.52A-10).
Front Seat Assembly Removal and Installation (Refer to
GROUP 52A, Front Seat P.52A-21).
² Strut Tower Bar (Refer to GROUP 42, Removal And
InstallationP.42-12.)
REMOVAL STEPS
BATTERY
AIR CLEANER BODY (REFER TO
GROUP 15, AIR CLEANER
P.15-4.)
1. HEATER HOSE CONNECTION
<>2. SUCTION PIPE CONNECTION
<>3. LIQUID PIPE CONNECTION
4. O-RING
REAR HEATER DUCT A AND B
(REFER TO P.55-175.)
5. JUNCTION BLOCKREMOVAL STEPS (Continued)
Page 872 of 1500
Page 875 of 1500
REFRIGERANT LINE
HEATER, AIR CONDITIONING AND VENTILATION55-174
3. Ensure a complete mating of joint before tightening the bolts
or nut.
4. Tighten the joint to the specific torque. For the nut joint, pay
special attention to following cautions.
Always use two wrenches to prevent the tubes from twist-
ing.
Pipes will rotate 15 - 20 clockwise during tightening, so
ensure final position is the correct location.
When finally tightening the pipes, do not rotate the fixed
side(female side).
Page 907 of 1500
HOW TO DIAGNOSE
GENERAL 00E-6
5. Ohmmeter
An ohmmeter is used to check continuity or measure
resistance of a switch or coil. If the measuring range has
been changed, the zero point must be adjusted before
measurement.
CHECKING FUSESM1001005000044
A blade type fuse has test taps provided to allow checking of
the fuse itself without removing it from the fuse block. The fuse
is okay if the test light comes on when its one lead is connected
to the test taps (one at a time) and the other lead is grounded.
Remember to turn the ignition switch to ON to ensure all cir-
cuits are live.
CAUTIONS IN EVENT OF BLOWN FUSE
When a fuse is blown, there are two probable causes. One is
that it is blown due to flow of current exceeding its rating. The
other is that it is blown due to repeated on/off current flowing
through it. Which of the two causes is responsible can be easily
determined by visual check as described below.
1. Fuse blown due to current exceeding rating
The illustration shows the state of a fuse blown due to this
cause. In this case, do not replace the fuse with a new one
hastily since a current heavy enough to blow the fuse has
flowed through it. First, check the circuit for shorts and check
for abnormal electric parts. After correcting shorts or
replacing parts, use only a fuse of the same capacity as a
replacement. Never use a fuse of larger capacity than the
original fuse. If a larger capacity fuse is used, electric parts
or wiring could be damaged, or could start a fire.
2. Fuse blown due to repeated turning current on and off
The illustration shows the state of a fuse blown due to
repeated current on/off. Normally, this type of problem
occurs after a fairly long period of use and is less frequent
than above. In this case, simply replace with a new fuse of
the same capacity.
