CONFIRM MALFUNCTION PART
Confirm the malfunction part with self-diagnosis.
Can the malfunction part be confirmed?
YES
Repair the malfunction part according to each diagnostics chart.
NO. Go to CHECK COMPARTMENT TEMPERATURE .
CHECK COMPARTMENT TEMPERATURE
Turn the A/C switch ON.
Set the temperature control dial to maximum cold position.
Check the compartment temperature changes.
Is the compartment temperature changed?
YES. Go to CHECK A/C SYSTEM RESPONSE .
NO. Go to COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM DOES NOT RESPOND PROMPTLY .
CHECK A/C SYSTEM RESPONSE
Change the temperature setting, and check the response of A/C system.
Does the A/C system respond quickly?
YES
A/C system is OK.
NO. Go to COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM DOES NOT RESPOND PROMPTLY .
BATTERY
Measure the battery voltage and specific gravity of electrolyte.
Standard voltage: 12 V
Specific gravity: Above 1.260
Check the condition of the fuses for A/C system power supply and other fuses.
Check the condition of the harnesses and harness connectors connection.
ASPIRATOR HOSE
Turn the ignition switch to ON and push the A/C switch.
Turn the temperature control dial to maximum hot position.
Turn the air flow control dial to "DEF" position.
Turn the fan speed control dial to MAX speed position.
Firmly hold a thin paper (b) in front of the in-vehicle sensor suction port (a) for the auto A/C control unit and check that the paper moves towards the port indicating that air is being sucked into the port.
Note. Ensure the paper does not get sucked into the port.
Scheme 91
If the paper does not move at all, remove the auto A/C control unit and check for improper connection of the aspirator hose (A), auto A/C control unit and heater unit, and secure as necessary.
Scheme 92
REFRIGERANT LINE
Check the connection for refrigerant line (A) and high-pressure pipe.
Scheme 93
CONTROL LINKAGE
Check the state of mode door linkage.
Check the state of air mix door linkage.
Check the state of intake door linkage.
CONTROL SWITCHES
Start and warm-up the engine completely.
Inspection using switches
| No. | Item to be checked | Switch position | Judgment standard |
|---|---|---|---|
| 1 | Air flow control dial | Turn the dial to the right. | Outlet opening (mode) switches AUTO ? VENT ? BI-LEVEL ? HEAT ? DEF/HEAT ? DEF each time turning the dial. |
| 2 | Fan speed control dial | Turn the dial to the right | Fan speed switches OFF ? AUTO ? 1st - 25th each time turning the dial. |
| 3 | FRESH/RECIRC switch | Press the FRESH/RECIRC switch. | Inlet opening switches RECIRC ? FRESH each time pressing the switch. |
| Press the FRESH/RECIRC switch longer (more than 1.0 seconds). | LED blinks twice, and switches to AUTO. | ||
| 4 | A/C switch | Turn the A/C switch to ON with the fan speed control dial position other than OFF. | LED comes on, and the compressor will be operated. |
| Press the FRESH/RECIRC switch longer (more than 1.0 seconds). | LED blinks twice, and switches to AUTO. | ||
| 5 | Auto function Operate from 1) in order. | Set the following dials and switches to AUTO. Air flow control dial Fan speed control dial FRESH/RECIRC switch A/C switch Turn the temperature control dial to the left fully, to set to the maximum cool position. | Outlet air temperature: COOL Fan speed: MAX Outlet opening: VENT Inlet opening: Internal air Compressor: AUTO |
| 3) Turn the temperature control dial to the right slowly, to change the setting gradually to the maximum hot position. | Outlet air temperature: COOL ? HOT Fan speed: AUTO Outlet opening: AUTO Inlet opening: AUTO Compressor: AUTO | ||
| 4) Turn the temperature control dial to the right fully, to set to the maximum hot position. | Outlet air temperature: HOT Fan speed: MAX Outlet opening: HEAT Inlet opening: External air Compressor: AUTO | ||
| 6 | Defroster interlock | Turn the air flow control dial to DEF or DEF/HEAT position. | Outlet air temperature: AUTO Fan speed: AUTO Outlet opening: DEF or DEF/HEAT Inlet opening: External air Compressor: ON |
| 7 | Rear window defogger switch | Press the rear window defogger switch. | LED comes on. |
CONTROL SWITCHES INSPECTION
Inspection of illumination control
| No. | Item to be checked | Switch operation | Judgment standard |
|---|---|---|---|
| 1 | Illumination | Turn the lighting switch to ON. | Illumination comes on. LED goes dim if it has been illuminated. |
ILLUMINATION CONTROL INSPECTION
PRECAUTIONS
Never connect the battery in reverse polarity.
The Auto A/C control module will be destroyed instantly.
Do not disconnect the battery cables while the engine is running.
- A large counter electromotive force will be generated in the alternator, and this voltage may damage electronic parts such as auto A/C control module.
Before disconnecting the connectors of each sensor and the auto A/C control module, be sure to turn off the ignition switch.
- The auto A/C control module may be damaged.
Every A/C-related part is a precision part. Do not drop them.
Airbag system wiring harness is routed near the A/C control panel (auto A/C control module) and junction box.
| IMPORTANT | All airbag system wiring harness and connectors are colored yellow. Do not use electrical test equipment on these circuits. Be careful not to damage the airbag system wiring harness when servicing the A/C control panel (auto A/C control module) and junction box. |
Scheme 94
- A/C compressor
- A/C relay
- Pressure switch
- Ambient sensor
Scheme 95
- Evaporator sensor
- Blower motor
- Blower motor resistor
- Intake door actuator
- Air mix door actuator
- Mode door actuator
- Sunload sensor
- In-vehicle sensor (built-in with Auto A/C control module)
Scheme 96
| Content | Connector & Terminal No. | Signal (V) |
|---|---|---|
| Battery power supply (Memory back-up) | B1 - B12 | Battery voltage, 13 - 14 (engine running) |
| IGN power supply | A8 - B12 | Battery voltage (ignition switch ON), 13 - 14 (engine running) |
| ACC power supply | B2 - B12 | Battery voltage, 0 (engine cranking), Battery voltage (engine running) |
| Auto A/C control module ground circuit | B12 - chassis ground | 0 (ignition switch ON) - circuit constantly grounded to chassis |
| Sensor ground circuit | B17 - chassis ground | 0 (ignition switch ON) - circuit constantly grounded to chassis |
| Ambient sensor | B9 - B17 | Approx. 5 (disconnect connector, and ignition switch ON) |
| Evaporator sensor | B7 - B17 | |
| Thermometer | B15 - B12 | |
| Sunload sensor | B16 - B17 | Approx. 5 (disconnect connector, and ignition switch ON) |
| Air mix door actuator | B5 - B1 | Battery voltage (ignition switch ON) |
| Air mix door actuator P.B.R. | A4 - B17 | LAN connection |
| Mode door actuator | B6 - B17 | Battery voltage (ignition switch ON) |
| Mode door actuator P.B.R. | A12 - B17 | LAN connection |
| Intake door FRS voltage | A15 - A7 | Battery voltage (FRESH/RECIRC switch OFF) |
| Intake door CIRC voltage | A7 - A15 | Battery voltage (FRESH/RECIRC switch ON) |
| Blower fan relay | B14 - body | Battery voltage (ignition switch ON) |
| A/C relay | B3 - B12 | 0 (ignition and A/C switches ON) Battery voltage (A/C switch OFF) |
| Illumination control signal | B10 - B20 | Battery voltage (ignition and lighting switches ON) |
| Rear window defogger | A13 - B12 | 0 (ignition switch ON, rear window defogger switch ON) |
CONNECTOR TERMINALS SIGNAL (V) REFERENCE
Scheme 97
- Air flow control dial
- Rear window defogger switch
- A/C switch
- FRESH/RECIRC switch
- Temperature control dial
- Fan speed control dial
CHECK SENSORS MALFUNCTION
Turn the fan speed control dial to AUTO position.
If the system has trouble for each sensor, rear window defogger switch LED is turned off.
If the system has no trouble, rear window defogger switch LED is illuminated.
Does the rear window defogger switch LED illuminate?
YES. Go to CHECK MODE DOOR POSITION SIGNAL .
NO. Go to CONFIRM MALFUNCTIONING SENSOR .
CONFIRM MALFUNCTIONING SENSOR
Turn the fan speed control dial to 1 - 6th position.
Turn the air flow control dial to each mode position, check each switch LED illumination according to sensor check table.
Do FRESH/RECIRC and A/C switch LED illuminate when turning the dial to each mode position?
YES. Go to CHECK MODE DOOR POSITION SIGNAL .
NO
Repair the malfunctioning sensor.
CHECK MODE DOOR POSITION SIGNAL
Turn the fan speed control dial to 7 - 12th position.
If the system has trouble for mode door position signal, rear window defogger switch LED is turned off.
If the system has no trouble, rear window defogger switch LED is illuminated.
Does the rear window defogger switch LED illuminate?
YES. Go to CHECK BLOWER FAN OPERATION .
NO
Check the mode door actuator circuit.
SENSOR CHECK TABLE
Note. When the sunload sensor is checked indoors or in the shade, open circuit might be indicated. Always check the sunload sensor at a place where sun shines directly on it.
| Air flow control dial position | Checked sensor | No trouble | Short circuit | Open circuit |
|---|---|---|---|---|
| VENT | Ambient sensor | A/C switch LED and FRESH/RECIRC switch LED illuminate | A/C switch LED illuminate | FRESH/RECIRC switch LED illuminate |
| BI-LEVEL | In-vehicle sensor | A/C switch LED and FRESH/RECIRC switch LED illuminate | A/C switch LED illuminate | FRESH/RECIRC switch LED illuminate |
| HEAT | Evaporator sensor | A/C switch LED and FRESH/RECIRC switch LED illuminate | A/C switch LED illuminate | FRESH/RECIRC switch LED illuminate |
| DEF/HEAT | Sunload sensor | A/C switch LED and FRESH/RECIRC switch LED illuminate | A/C switch LED illuminate | FRESH/RECIRC switch LED illuminate |
| DEF | Air mix door motor (Potentiometer balance resistor) | A/C switch LED and FRESH/RECIRC switch LED illuminate | A/C switch LED illuminate | |
SENSOR CHECKING REFERENCE
OPERATING MODE TABLE
| Operation | Air flow control dial position | ||||
|---|---|---|---|---|---|
| VENT | BI-LEVEL | HEAT | DEF/HEAT | DEF | |
| Air outlet | VENT | BI-LEVEL | HEAT | DEF/HEAT | DEF |
| Air inlet | RECIRC | RECIRC | RECIRC | FRESH | FRESH |
| Air mix door | FULL COOL | FULL COOL | FULL HOT | FULL HOT | FULL COOL |
| Blower fan | 5V | 5V | 8V | 10V | Power supply voltage |
| A/C compressor | ON | OFF | OFF | ON | ON |
OPERATING MODE REFERENCE
CHECK FUSE
Turn the ignition switch to OFF.
Remove the fuse No. 2 from main fuse box.
Check the condition of fuse.
Is the fuse blown-out?
YES
Replace the fuse.
NO. Go to CHECK FUSE .
Turn the ignition switch to OFF.
Remove the fuses No. 9 and No. 17 from fuse & relay box.
Check the condition of fuse.
Is the fuse blown-out?
YES
Replace the fuse.
NO. Go to CHECK AUTO A/C CONTROL MODULE POWER CIRCUIT .
CHECK AUTO A/C CONTROL MODULE POWER CIRCUIT
Pull out the A/C control module connector.
Measure the voltage between auto A/C control module connector terminal and chassis ground when turning ignition switch to OFF.
Connector & terminal
(B283) No. 1 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK AUTO A/C CONTROL MODULE POWER CIRCUIT .
NO
Repair the short circuit in harness for power supply line.
Measure the voltage between auto A/C control module connector terminal and chassis ground when turning the ignition switch to ACC.
Connector & terminal
(B283) No. 2 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK AUTO A/C CONTROL MODULE POWER CIRCUIT .
NO
Repair the short circuit in harness for power supply line.
Measure the voltage between auto A/C control module connector terminal and chassis ground when turning the ignition switch to ON.
Connector & terminal
(B282) No. 8 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK AUTO A/C CONTROL MODULE GROUND CIRCUIT .
NO
Repair the short circuit in harness for power supply line.
CHECK AUTO A/C CONTROL MODULE GROUND CIRCUIT
Measure the resistance of harness between auto A/C control module and chassis ground.
Connector & terminal
(B283) No. 12 - Chassis ground
Is the resistance less than 5 O?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO
Repair the short circuit in harness for ground line.
CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
Remove the No. 1, No. 2 and No. 17 fuses in fuse & relay box.
Check the condition of fuses.
Are any of the fuses blown-out?
YES
Replace the fuse.
NO. Go to CHECK POWER SUPPLY TO BLOWER FAN MOTOR .
CHECK POWER SUPPLY TO BLOWER FAN MOTOR
Turn the ignition switch to ON.
Turn the fan speed control dial to the right.
Measure the voltage between blower fan motor and chassis ground.
Connector & terminal
(B87) No. 1 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK BLOWER FAN MOTOR RELAY .
NO
Repair the open circuit in harness for blower fan motor power supply line.
CHECK BLOWER FAN MOTOR RELAY
Turn the ignition switch to OFF.
Remove the blower fan motor relay.
Connect the battery positive (+) terminal to No. 1 terminal and negative (- ) terminal to No. 3 terminal of blower fan motor connector.
Measure the resistance between No. 2 and No. 4 terminals.
Terminals
No. 2 - No. 4
Is the resistance less than 1 O?
YES. Go to CHECK BLOWER FAN MOTOR .
NO
Replace the blower fan motor relay.
CHECK BLOWER FAN MOTOR
Disconnect the connector from blower fan motor.
Connect the battery positive (+) terminal to No. 1 terminal and negative (- ) terminal to No. 2 terminal of blower fan motor connector.
Make sure that the blower fan motor is operated.
Does the blower fan motor operate?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO
Replace the blower fan motor.
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
Turn the ignition switch to OFF.
Remove the No. 2 fuse in main fuse box.
Check the condition of fuse.
Is the fuse blown-out?
YES
Replace the fuse.
NO. Go to CHECK POWER SUPPLY TO MAGNET CLUTCH OF A/C COMPRESSOR .
CHECK POWER SUPPLY TO MAGNET CLUTCH OF A/C COMPRESSOR
Start the engine, and turn A/C switch to ON.
Set the temperature control dial to maximum cold position.
Measure the voltage between magnet clutch connector and chassis ground.
Connector & terminal
(F24) No. 1 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK SIGNAL VOLTAGE TO A/C RELAY .
NO
Repair the open circuit in harness for power supply line of the A/C compressor.
CHECK SIGNAL VOLTAGE TO A/C RELAY
Turn the ignition switch to ON.
Turn the A/C switch to ON.
Measure the signal voltage between A/C relay and chassis ground.
Connector & terminal
(F27) No. 14 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK A/C RELAY .
NO
Repair the open circuit in harness for A/C relay signal circuit.
CHECK A/C RELAY
Remove the A/C relay in main fuse box.
Check the A/C relay.
Is the operation of the relay OK?
YES. Go to CHECK OPERATION OF MAIN FAN MOTOR .
NO
Replace the A/C relay.
CHECK POWER SUPPLY TO MAIN FAN MOTOR
| IMPORTANT | Be careful not to overheat the engine during repair. |
Turn the ignition switch to OFF.
Disconnect the connector from main fan motor.
Start the engine, and warm it up until engine coolant temperature increases over 95°C (203°F).
Stop the engine and turn ignition switch to ON.
Measure the voltage between main fan motor connector and chassis ground.
Connector & terminal
(F17) No. 1, 2 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK GROUND CIRCUIT OF MAIN FAN MOTOR .
NO
Repair the open circuit in harness for power supply circuit.
CHECK GROUND CIRCUIT OF MAIN FAN MOTOR
Turn the ignition switch to OFF.
Measure the resistance between main fan motor connector and chassis ground.
Connector & terminal
(F17) No. 3, 4 - Chassis ground
Is the resistance less than 1 O?
YES. Go to CHECK POOR CONTACT .
NO
Repair the open circuit in harness between main fan motor connector and chassis ground.
CHECK POOR CONTACT
Check poor contact in main fan motor connector.
Is there poor contact in main fan motor connector?
YES
Repair the poor contact in main fan motor connector.
NO. Go to CHECK MAIN FAN MOTOR .
CHECK MAIN FAN MOTOR
Connect the battery positive (+) terminal to terminal No. 1 and 2, and negative (- ) terminal to terminal No. 3 and 4.
Does the main fan rotate?
YES
Repair the poor contact in main fan motor connector.
NO
Replace the main fan motor with a new one.
CHECK POWER SUPPLY TO SUB FAN MOTOR
| IMPORTANT | Be careful not to overheat the engine during repair. |
Turn the ignition switch to OFF.
Disconnect the connector from sub fan motor.
Start the engine, and warm it up until engine coolant temperature increases over 100°C (212°F).
Stop the engine and turn the ignition switch to ON.
Measure the voltage between sub fan motor connector and chassis ground.
Connector & terminal
(F16) No. 1, 2 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK GROUND CIRCUIT OF SUB FAN MOTOR .
NO
Repair the open circuit in harness for power supply circuit.
CHECK GROUND CIRCUIT OF SUB FAN MOTOR
Turn the ignition switch to OFF.
Measure the resistance between sub fan motor connector and chassis ground.
Connector & terminal
(F16) No. 3, 4 - Chassis ground
Is the resistance less than 1 O?
YES. Go to CHECK POOR CONTACT .
NO
Repair the open circuit in harness between sub fan motor connector and chassis ground.
Check poor contact in sub fan motor connector.
Is there poor contact in sub fan motor connector?
YES
Repair the poor contact in sub fan motor connector.
NO. Go to CHECK SUB FAN MOTOR .
CHECK SUB FAN MOTOR
Connect the battery positive (+) terminal to terminal No. 1 and 2, and negative (- ) terminal to terminal No. 3 and 4.
Does the sub fan rotate?
YES
Repair the poor contact in sub fan motor connector.
NO
Replace the sub fan motor with a new one.
CHECK EACH SENSOR AND POTENTIOMETER
Check the sensors and potentiometer for proper operation using the self-diagnostic function.
Is the operation of each sensor and potentiometer normal?
YES. Go to CHECK CONNECTION OF ASPIRATOR DUCT .
NO
Check the sensor and circuit.
CHECK CONNECTION OF ASPIRATOR DUCT
Make sure the connection of aspirator duct is correct.
Is the connection of aspirator duct correct?
YES
Repair the aspirator duct connection.
NO. Go to CHECK EACH ACTUATOR .
CHECK EACH ACTUATOR
Check the actuators for proper operation using the self-diagnostic function.
Is the operation of each actuator normal?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL UNIT CONNECTOR .
NO
Check the actuator and circuit.
CHECK POOR CONTACT IN AUTO A/C CONTROL UNIT CONNECTOR
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
Remove the No. 17 fuse in fuse & relay box.
Check the condition of fuse.
Is the fuse blown-out?
YES
Replace the fuse.
NO. Go to CHECK SIGNAL VOLTAGE .
CHECK SIGNAL VOLTAGE
Change the air intake to RECIRC by pushing FRESH/RECIRC switch.
Measure the voltage between auto A/C control module and chassis ground.
Connector & terminal
(B282) No. 15 (+) - Chassis ground (- )
Is the voltage less than 1 V?
YES. Go to CHECK SIGNAL VOLTAGE .
NO
Repair the short circuit in harness for power supply line.
Change the air intake to FRESH with pushing FRESH/RECIRC switch.
Measure the voltage between auto A/C control module and chassis ground.
Connector & terminal
(B282) No. 7 (+) - Chassis ground (- )
Is the voltage less than 1 V?
YES. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND FRESH/RECIRC ACTUATOR .
NO
Repair the short circuit in harness for power supply line.
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
CHECK POWER SUPPLY FOR AUTO A/C CONTROL MODULE SIDE
Turn the ignition switch to ON.
Turn the A/C switch to ON.
Measure the voltage between auto A/C control module harness connector terminal and chassis ground.
Connector & terminal
(B283) No. 6 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK POWER SUPPLY FOR ACTUATOR SIDE .
NO
Replace the auto A/C control module.
CHECK POWER SUPPLY FOR ACTUATOR SIDE
Measure the voltage between mode door actuator harness connector terminal and chassis ground.
Connector & terminal
(B77) No. 1 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK SIGNAL FOR AUTO A/C CONTROL MODULE SIDE .
NO
Repair the open circuit in harness between auto A/C control module and mode door actuator.
CHECK SIGNAL FOR AUTO A/C CONTROL MODULE SIDE
Measure the voltage between auto A/C control module harness connector terminal and chassis ground with oscilloscope.
Connector & terminal
(B282) No. 12 (+) - Chassis ground (- )
Is the voltage approx. 5.5 V?
YES. Go to CHECK SIGNAL FOR ACTUATOR SIDE .
NO
Replace the auto A/C control module.
CHECK SIGNAL FOR ACTUATOR SIDE
Measure the voltage between mode door actuator harness connector terminal and chassis ground.
Connector & terminal
(B77) No. 3 (+) - Chassis ground (- )
Is the voltage approx. 5.5 V?
YES. Go to CHECK GROUND CIRCUIT OF ACTUATOR .
NO
Repair the open circuit in harness between auto A/C control module and mode door actuator.
CHECK GROUND CIRCUIT OF ACTUATOR
Turn the ignition switch and A/C switch to OFF.
Measure the resistance between mode door actuator harness connector terminal and chassis ground.
Connector & terminal
(B77) No. 2 - Chassis ground
Is the resistance less than 1 O?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO
Repair the open circuit in harness between mode door actuator and chassis ground.
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
Turn the ignition switch to ON.
Turn the A/C switch to ON.
Measure the voltage between auto A/C control module harness connector terminal and chassis ground.
Connector & terminal
(B283) No. 5 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK POWER SUPPLY FOR ACTUATOR SIDE .
NO
Replace the auto A/C control module.
Measure the voltage between air mix door actuator harness connector terminal and chassis ground.
Connector & terminal
(B293) No. 1 (+) - Chassis ground (- )
Is the voltage more than 10 V?
YES. Go to CHECK SIGNAL FOR AUTO A/C CONTROL MODULE SIDE .
NO
Repair the open circuit in harness between auto A/C control module and air mix door actuator.
Measure the voltage between auto A/C control module harness connector terminal and chassis ground with oscilloscope.
Connector & terminal
(B282) No. 4 (+) - Chassis ground (- )
Is the voltage approx. 5.5 V?
YES. Go to CHECK SIGNAL FOR ACTUATOR SIDE .
NO
Replace the auto A/C control module.
Measure the voltage between air mix door actuator harness connector terminal and chassis ground with oscilloscope.
Connector & terminal
(B293) No. 3 (+) - Chassis ground (- )
Is the voltage approx. 5.5 V?
YES. Go to CHECK GROUND CIRCUIT OF ACTUATOR .
NO
Repair the open circuit in harness between auto A/C control module and air mix door actuator.
Turn the ignition switch and A/C switch to OFF.
Measure the resistance between air mix door actuator harness connector terminal and chassis ground.
Connector & terminal
(B293) No. 2 - Chassis ground
Is the resistance less than 1 O?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO
Repair the open circuit in harness between air mix door actuator and chassis ground.
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
CHECK AMBIENT SENSOR
Turn the ignition switch to OFF.
Disconnect the connector from ambient sensor.
Measure the resistance between connector terminals of ambient sensor.
Terminals
No. 1 - No. 2
Is the resistance approx. 2.2 kO at 25°C (77°F)?
YES. Go to CHECK INPUT SIGNALS FOR AMBIENT SENSOR .
NO
Replace the ambient sensor.
CHECK INPUT SIGNALS FOR AMBIENT SENSOR
Turn the ignition ON.
Measure the voltage between (F78) connector terminals.
Connector & terminal
(F78) No. 1 (+) - No. 2 (- )
Is the voltage approx. 5 V?
YES. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND AMBIENT SENSOR .
NO. Go to CHECK OUTPUT SIGNALS FROM AUTO A/C CONTROL MODULE .
CHECK OUTPUT SIGNALS FROM AUTO A/C CONTROL MODULE
Turn the ignition switch to OFF.
Pull out the auto A/C control unit.
Disconnect the connector from ambient sensor.
Turn the ignition switch to ON.
Measure the voltage between connector terminals of auto A/C control module.
Connector & terminal
(B283) No. 9 (+) - No. 17 (- )
Is the voltage approx. 5 V?
YES. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND AMBIENT SENSOR .
NO. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
CHECK EVAPORATOR SENSOR
Turn the ignition switch to OFF.
Remove the glove box.
Disconnect the connector from evaporator sensor.
Measure the resistance between connector terminals of evaporator sensor.
Terminals
No. 1 - No. 2
Is the resistance approx. 3.3 kO at 20°C (68°F)?
YES. Go to CHECK INPUT SIGNALS FOR EVAPORATOR SENSOR .
NO
Replace the evaporator sensor.
CHECK INPUT SIGNALS FOR EVAPORATOR SENSOR
Turn the ignition switch to ON.
Measure the voltage between (B256) connector terminal and chassis ground.
Connector & terminal
(B256) No. 2 (+) - Chassis ground (- )
Is the voltage approx. 5 V?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO. Go to CHECK OUTPUT SIGNALS FROM AUTO A/C CONTROL MODULE .
Turn the ignition switch to OFF.
Pull out the auto A/C control module.
Turn the ignition switch to ON.
Measure the voltage between auto A/C control module connector terminals.
Connector & terminal
(B283) No. 7 (+) - No. 17 (- )
Is the voltage approx. 5 V?
YES. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND EVAPORATOR SENSOR .
NO. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.
CHECK INPUT VOLTAGE TO SUNLOAD SENSOR
Turn the ignition switch to ON.
Measure the input voltage to sunload sensor.
Connector & terminal
(i51) No. 2 (+) - Chassis ground (- )
Is the voltage approx. 5 V?
YES. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND SUNLOAD SENSOR .
NO. Go to CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND SUNLOAD SENSOR .
CHECK THE INPUT VOLTAGE TO AUTO A/C CONTROL MODULE
Connect the auto A/C control module connector.
Turn the ignition switch to ON.
Measure the voltage between auto A/C control module connector terminals.
Connector & terminal
(B283) No. 16 (+) - (B283) No. 17 (- )
Is the voltage approx. 2.5 V?
YES. Go to CHECK POOR CONTACT IN AUTO A/C CONTROL MODULE CONNECTOR .
NO
Replace the sunload sensor.
Check poor contact in auto A/C control module connector.
Is there poor contact in connector?
YES
Repair the connector.
NO
Replace the auto A/C control module.