Contents Section: Automatic HVAC System All sections

HVAC System (Auto AC) (Diagnostics): Other Subaru Forester SG рестайлинг

Automatic HVAC System 17 illustrations ~1051 words

PROCEDURE

StepCheckYesNo
1 START INSPECTIONS. Perform the pre-inspection. INSPECTION GENERAL DESCRIPTION. > Perform the self-diagnosis. OPERATION DIAGNOSTIC CHART FOR SELF-DIAGNOSIS. >Does the self-diagnosis operate?Go to step 2.A/C OR SELF-DIAGNOSIS SYSTEMS DO NOT OPERATE DIAGNOSTICS FOR A/C SYSTEM MALFUNCTION. >
2 IDENTIFY MALFUNCTION PART. Identify the malfunction part with self-diagnosis.Can the malfunction part be confirmed?Repair the malfunctioning part in accordance with each diagnostic chart.Go to step 3.
3 CHECK COMPARTMENT TEMPERATURE. Turn on the A/C switch. Turn the temperature control dial at maximum cool position. Check the compartment temperature change.Does the compartment temperature change?Go to step 4.COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM DOES NOT RESPOND PROMPTLY DIAGNOSTICS FOR A/C SYSTEM MALFUNCTION. >
4 CHECK A/C SYSTEM RESPONSE. Change the temperature setting, and check the response of A/C system.Does the A/C system respond quickly?A/C system is normal.COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM DOES NOT RESPOND PROMPTLY DIAGNOSTICS FOR A/C SYSTEM MALFUNCTION. >

BASIC DIAGNOSTIC PROCEDURE CHART

CAUTION

  1. Never connect the battery in reverse polarity. Doing so may immediately damage the auto A/C control module.
  2. Do not disconnect the battery terminals while the engine is running. A large counter electromotive force will be generated in the generator, and this voltage may damage electronic parts such as auto A/C control module etc.
  3. Before disconnecting the connectors of sensors and the auto A/C control module, be sure to turn off the ignition switch. Otherwise, the auto A/C control module may be damaged.
  4. Every A/C-related part is a precision part. Do not drop them.
  5. The airbag system wiring harness is routed near the A/C control panel (auto A/C control module) and junction box.
CAUTIONThe airbag system wiring harnesses and connectors are all yellow in color. 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.

BATTERY

  1. Measure the battery voltage and check electrolyte. Standard voltage: 12 V Specific gravity: 1.260 or more
  2. Check the condition of the fuses for A/C system power supply and other fuses.
  3. Check the condition of harness and harness connector connections.

Scheme 4

Scheme 4: ASPIRATOR HOSE
  1. Turn the ignition switch to ON.
  2. Turn the temperature control dial at maximum hot position.
  3. Set the air flow control dial to the DEF position.
  4. Turn the fan speed control dial to the maximum position.
  5. Approach a strip of paper in front of the in-vehicle sensor suction port (A) of the auto A/C control module, and check that air is being sucked into the port by seeing the paper moving towards the port. NOTE: Be careful not to let the paper get sucked into the port. Hold the paper approx. 5 mm (0.02 in) away from port when the suction force is not very strong.
  6. If the paper does not move at all, remove the lower cover REMOVAL Control Unit. > and check for improper connection of the aspirator hose, lower cover, and heater unit, and fix them if necessary.

REFRIGERANT LINE

Check the connection for A/C line (A) and high-pressure pipe.

Scheme 5

Scheme 5: REFRIGERANT LINE

CONTROL LINKAGE

  1. Check the state of mode door linkage.
  2. Check the state of air mix door linkage.
  3. Check the state of RESH/RECIRC door linkage.

CONTROL SWITCHES

Start the engine and warm-up completely.

  1. Inspection using switches CONTROL SWITCHES INSPECTION CHART No. Point to check Switch operation Judgment standard 1 Air flow control dial Turn the dial to the right. Outlet opening switches in order to AUTO --> VENT --> BILEVEL --> HEAT --> DEF/HEAT --> DEF each time the dial is turned. 2 Fan speed control dial Turn the dial to the right. Fan speeds switch OFF --> AUTO --> 1st --> 2nd --> 3rd --> 4th -->5th -->6th --> 7th each time the dial is turned. 3 FRESH/RECIRC switch Press the FRESH/RECIRC switch. Inlet opening switches RECIRC --> FRESH --> RECIRC each time the switch is pressed. (The LED lights for RECIRC.) Press the FRESH/RECIRC switch for a longer period of time. (1 second or more) The LED blinks twice and the system switches to AUTO. 4 A/C switch Turn the A/C switch to ON with the fan speed control dial is set to other than OFF position. The LED lights and the compressor operates. Press the FRESH/RECIRC switch for a longer period of time. (1 second or more) The LED blinks twice and the system switches to AUTO. 5 Auto function Operate in order from 1). Set the following dial and switch to AUTO. Air flow control dial Fan speed control dial FRESH/RECIRC switch A/C switch Turn the temperature control dial completely to the left, and set to the maximum cool position. Outlet air temperature: COOL Fan speed: Max. Outlet opening: VENT Inlet opening: RECIRC Compressor: AUTO 3) Turn the temperature control dial to the right slowly up to the maximum warm position. Outlet air temperature: COOL --> HOT Fan speed: AUTO Outlet opening: AUTO Inlet opening: AUTO Compressor: AUTO 4) Turn the temperature control dial fully to the right, to the maximum hot position. Outlet air temperature: HOT Fan speed: Max. Outlet opening: HEAT Inlet opening: FRESH Compressor: AUTO 6 Defroster Interlock Function Set the air flow control dial to the DEF or the DEF/HEAT position. Outlet opening: AUTO Fan speed: AUTO Outlet opening: DEF or DEF/HEAT Inlet opening: FRESH Compressor: ON 7 Rear defogger switch Press the rear defogger switch. Does the LED light?
  2. Inspection of illumination control
No.Point to checkSwitch operationJudgment standard
1IlluminationTurn the lighting switch ON.Illumination comes on. If the LED lights, the LED will dim.

ILLUMINATION CONTROL INSPECTION CHART

Scheme 6

Scheme 6: ENGINE COMPARTMENT

Scheme 7

Scheme 7: PASSENGER COMPARTMENT

Scheme 8

Scheme 8: ELECTRICAL SPECIFICATION
Connector & Terminal No.ContentMeasuring conditionSpecified value
B9Mode door actuatorSwitch the outlet opening to VENT --> DEF.(2)
B8Switch the outlet opening to DEF --> VENT.
B7Air mix door actuatorSwitching the air mix door from COOL --> HOT(1)
B6Switching the air mix door from HOT --> COOL
B5Ignition power supplyIgnition switch: ONBattery voltage
B4Battery power supplyIgnition switch: OFF, ACC, ONBattery voltage
B3Sunload sensorIgnition switch: ON, With Normal Sunload (No sunload: 5 V)3V
B2Evaporator sensorIgnition switch: ONLess than 5 V
B1Air mix door actuator PBR signalAir mix door: COOL position0.5 V
Air mix door: HOT position4.5 V
B20Intake door actuator signalInlet opening: FRESH (Other positions: 12 V)0V
B19Inlet opening: MIX (Other positions: 12 V)0V
B18Inlet opening: RECIRC (Other positions: 12 V)0V
B17A/C ON signalA/C: ON (A/C OFF: 0 V)8 - 10V
B16Blower motor control(3)(3)
B15Blower fan ON signalWhen blower fan is rotating (Not rotating: 12 V)0V
B13Engine coolant temperature sensorWhen the engine coolant temperature is 49°C (120°F).8.9 V
B12In-vehicle sensor
B11GroundContinuity to chassis ground0 ohms
A7Air mix door actuator PBR specified voltageIgnition switch: ON5V
A5Mode door actuator position detection signalOutlet openingBI-LEVEL, DEF5V
VENT, HEAT, DEF/HEAT0 V
A4Mode door actuator position detection signalOutlet openingHEAT, DEF/HEAT, DEF5V
VENT, BI-LEVEL0 V
A1Illumination power supplyIgnition switch: ON, Light switch: ONBattery voltage
Ignition switch: ON, Light switch: OFF0V
A16Sensor ground circuitContinuity to chassis ground0 ohms
A14Combination meter (Ambient temperature signal)*3*3
A13Mode door actuator position detection signalOutlet openingVENT, BI-LEVEL, HEAT5V
DEF/HEAT, DEF0V
A12Mode door actuator position detection signalOutlet openingVENT, DEF/HEAT5V
BI-LEVEL, HEAT, DEF0V
A10A/C cut signalA/C: ONBattery voltage
Pressure switch operated0V
A9Illumination groundContinuity to chassis ground0 ohms
(1) Shows the battery voltage while the motor is running. When stopped, it will output 0 V, or the pulse signals of the battery voltage. (2) Shows the battery voltage while the motor is running. When stopped, it shows 0 V. (3) Unable to measure the voltage because it is a pulse signal.
(1)Shows the battery voltage while the motor is running. When stopped, it will output 0 V, or the pulse signals of the battery voltage.
(2)Shows the battery voltage while the motor is running. When stopped, it shows 0 V.
(3)Unable to measure the voltage because it is a pulse signal.

TERMINALS REFERENCE

SENSOR CHECK TABLE

Note. When checking the sunload sensor indoor or in the shade, an open circuit might be indicated. Always check the sunload sensor at a location exposed to direct sunlight.

No.Target for inspectionAir flow control dial position
1In-vehicle sensorAUTO
2Ambient sensorVENT
3Evaporator sensorB/L
4Sunload sensor *1HEAT
5Air mix door actuator PBRD/H
6Meter communicationDEF
(1) For a sunload sensor open circuit, only the current malfunction is displayed. (However, it is possible to display past failures for short circuits.)
(1)For a sunload sensor open circuit, only the current malfunction is displayed. (However, it is possible to display past failures for short circuits.)

SENSOR CHECK

Scheme 9

Scheme 9

Scheme 10

Scheme 10
  1. The LED blinking pattern for open circuit failures
  2. The LED blinking pattern for short circuit failures

OPERATING MODE TABLE

Step12345678
Fan control dial positionAUTO1st2nd3rd4th5th6th7th
Fan speed (%)24.024.034.045.042.059.071.0100.0
Mode door actuatorVENTVENTVENTB/LHEATHEATD/HDEF
Intake door actuatorFRERECRECFREFREFREFREFRE
Air mix door actuatorMaximum cool (0%)Maximum cool (0%)Maximum cool (0%)Mid (50%)Mid (50%)Maximum hot (100%)Maximum hot (100%)Maximum hot (100%)
Compressor (Magnet clutch)OFFONONONONONONON

OPERATING MODE

BLOWER FAN DOES NOT ROTATE

TROUBLE SYMPTOM

  1. Blower motor does not rotate.
  2. Blower motor does not change speeds. WIRING DIAGRAM

Scheme 11

Scheme 11
StepCheckYesNo
1 CHECK FUSE. Remove fuse No. 1, 2 and 17 from fuse & relay box. Check the condition of fuse.Is any of the fuses blown out?Replace the fuse.Go to step 2.
2 CHECK POWER SUPPLY FOR BLOWER MOTOR. Turn the ignition switch to ON. Turn the fan speed control dial to the right. Measure the voltage between blower motor and chassis ground. Connector & terminal (B87) No. 1 (+) - Chassis ground (-)Is the voltage 8 V or more (at normal temperature)?Go to step 3.Repair the open circuit of blower motor power supply line harness.
3 CHECK BLOWER MOTOR RELAY. Turn the ignition switch to OFF. Remove the blower motor relay. Connect the battery positive (+) terminal to terminal No. 1 of blower motor connector, and negative (-) terminal to terminal No. 3. Measure the resistance between terminals No.2 and 4. Terminals No.2 -No. 4Is the resistance less than 1 ohms?Go to step 4.Replace the blower motor relay.
4 CHECK BLOWER MOTOR. Disconnect the connector from the blower motor. Connect the battery positive (+) terminal to terminal No. 1 of the blower motor connector, and negative (-) terminal to terminals No. 2 and 5. Make sure the blower motor runs.Does the blower motor run?Go to step 5.Replace the blower motor.
5 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

COMPARTMENT TEMPERATURE DOES NOT CHANGE, OR A/C SYSTEM DOES NOT RESPOND PROMPTLY

TROUBLE SYMPTOM

  1. Compartment temperature does not change.
  2. A/C system does not respond quickly? WIRING DIAGRAM
  1. Non-turbo model

Scheme 12

Scheme 12
  1. Turbo model

Scheme 13

Scheme 13
StepCheckYesNo
1 CHECK FUSE. Turn the ignition switch to OFF. Remove the main fan fuse and sub fan fuse of the main fuse box. Check the condition of fuse.Is the fuse blown out?Replace the fuse.Go to step 2.
2 CHECK POWER SUPPLY FOR PRESSURE SWITCH Disconnect the connector from the pressure switch. Turn the ignition switch to ON. Measure the voltage between pressure switch harness connector and chassis ground. Connector & terminal (B7) No. 1 (+) - Chassis ground (-)Is the voltage more than 10 V?Go to step 3.Repair the open circuit in harness of pressure switch power supply circuit.
3 CHECK HARNESS BETWEEN PRESSURE SWITCH AND A/C RELAY. Turn the ignition switch to OFF. Remove the A/C relay of the fuse box. Measure the resistance of the A/C relay and pressure switch connector. Connector & terminal Non-turbo model (F27) No. 17 - (B7) No. 2: Turbo model (F9) No. 7 - (B7) No. 2Is the resistance less than 1 ohms?Go to step 4.Repair the open circuit of the harness between the A/C relay and pressure switch.
4 CHECK PRESSURE SWITCH. Measure the resistance between the pressure switch terminals. Terminals No. 1 - No.2Is the resistance less than 1 ohms?Go to step 5.Replace the pressure switch.
5 CHECK A/C CUT SIGNAL CIRCUIT. Disconnect the connector from the auto A/C control module. Measure the resistance between the auto A/C control module and the pressure switch connector. Connector & terminal (148) No. 10 - (B7) No. 2Is the resistance less than 1 ohms?Go to step 6.Repair the open circuit of the harness between auto A/C control module and pressure switch.
6 CHECK A/C ON SIGNAL CIRCUIT. Disconnect the connectors from ECM. Measure the resistance between the ECM and the auto A/C control module connector. Connector & terminal Non-turbo model (B136) No. 23 - (i49) No. 17: Turbo model (B136) No. 24 - (i49) No. 17Is the resistance less than 1 ohms?Go to step 7.Repair the open circuit of the harness between auto A/C control module and ECM.
7 CHECK A/C RELAY. Remove the A/C relay of the fuse box. Check the A/C relay. INSPECTION Relay and Fuse. >Does the relay operate normally?Go to step 8.Replace the A/C relay.
8 CHECK POWER SUPPLY TO MAGNET CLUTCH OF A/C COMPRESSOR. Turn the ignition switch to OFF, and connect the A/C relay and all disconnected connectors. Start the engine and turn the A/C switch ON. Turn the temperature control dial at maximum cool position. Measure the voltage between magnet clutch connector and chassis ground. Connector & terminal (F24) No. 1 (+) - Chassis ground (-)Is the voltage 10.5 V or more (at normal temperature)?Go to step 9.Repair the open circuit in harness of the A/C compressor power circuit.
9 CHECK MAIN FAN MOTOR OPERATION. Start the engine. Turn on the A/C switch. Check the operation of the main fan motor.Does the main fan motor operate normally?Go to step 14 .Go to step 10 .
10 CHECK POWER SUPPLY TO MAIN FAN MOTOR. CAUTION: Be careful not to overheat the engine during repair. Turn the ignition switch to OFF. Disconnect the connector from the main 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 main fan motor connector and chassis ground. Connector & terminal (F17) No. 1 (+) - Chassis ground (-)Is the voltage more than 10 V?Go to step 11 .Repair the open circuit in harness of main fan motor power supply circuit.
11 CHECK MAIN FAN MOTOR GROUND CIRCUIT. Turn the ignition switch to OFF. Measure the resistance between main fan motor connector and chassis ground. Connector & terminal (F17) No. 2 - Chassis groundIs the resistance less than 1 ohms?Go to step 12 .Repair the open circuit in harness of main fan motor ground circuit.
12 CHECK MAIN FAN MOTOR. Connect the positive terminal (+) of the battery to No. 1 terminal of the main fan motor connector, and the negative (-) terminal to No. 2 terminal. Check that the main fan motor is running.Is the main fan motor rotating?Go to step 13 .Replace the main fan motor with a new one.
13 CHECK POOR CONTACT OF THE MAIN FAN MOTOR CONNECTOR. Check poor contact of main fan motor connector.Is there poor contact in the connector?Go to step 14 .Repair the poor contact of main fan motor connector.
14 CHECK SUB FAN MOTOR OPERATION. Start the engine and turn the A/C switch ON. Check the operation of the sub fan motor.Does the sub fan motor operate normally?Go to step 19 .Go to step 15 .
15 CHECK POWER SUPPLY TO SUB FAN MOTOR. CAUTION: Be careful not to overheat the engine during repair. Turn the ignition switch to OFF. Disconnect the connector from the 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 (+) - Chassis ground (-)Is the voltage more than 10 V?Go to step 16 .Repair the open circuit in the harness of the sub fan motor power supply circuit.
16 CHECK SUB FAN MOTOR GROUND CIRCUIT. Turn the ignition switch to OFF. Measure the resistance between the sub fan motor connector and chassis ground. Connector & terminal (F16) No. 2 - Chassis groundIs the resistance less than 1 ohms?Go to step 17 .Repair the open circuit in the harness of sub fan motor ground circuit.
17 CHECK SUB FAN MOTOR. Connect the positive terminal (+) of the battery to No. 1 terminal of the sub fan motor connector, and the negative (-) terminal to No. 2 terminal. Check that the sub fan motor is running.Does the sub fan motor rotate?Go to step 18 .Replace the sub fan motor with a new one.
18 CHECK POOR CONTACT OF THE SUB FAN MOTOR CONNECTOR. Check for poor contact of sub fan motor connector.Is there poor contact in the connector?Repair the poor contact of sub fan motor connector.Go to step 19 .
19 CHECK FOR POOR CONTACT OF THE AUTO A/C CONTROL MODULE CONNECTOR. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.
CAUTION
Be careful not to overheat the engine during repair.
CAUTION
Be careful not to overheat the engine during repair.

DIAGNOSTIC PROCEDURE CHART

INTAKE DOOR ACTUATOR

TROUBLE SYMPTOM

FRESH/RECIRC mode is not changed.

WIRING DIAGRAM

Scheme 14

Scheme 14: INTAKE DOOR ACTUATOR
StepCheckYesNo
1 CHECK POWER SUPPLY FOR INTAKE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the intake door actuator connector. Turn the ignition switch to ON. Measure the voltage between intake door actuator connector and chassis ground. Connector & terminal (B91) No. 4 (+) - Chassis ground (-)Is the voltage 7 V or more (at normal temperature)?Go to step 2.Check for open or short circuit in the harness between intake door actuator and fuse.
2 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND INTAKE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the auto A/C control module connector. Measure the resistance between intake door actuator connector and auto A/C control module connector. Connector & terminal (i49) No. 18 - (B91) No. 2: (i49) No. 20 - (B91) No. 1: (i49) No. 19 - (B91) No. 3Is the resistance less than 1 ohms?Go to step 3.Repair the open circuit in harness between auto A/C control module and intake door actuator.
3 CHECK OPERATION OF INTAKE DOOR ACTUATOR. Connect the intake door actuator connector. Ground the auto A/C control module connector with a suitable wire. Turn the ignition switch to ON, and check the operation of intake door actuator. Connector & terminal (i49) No. 20 - Chassis groundIs the intake door actuator moved to FRESH?Go to step 4.Replace the intake door actuator.
4 CHECK OPERATION OF INTAKE DOOR ACTUATOR. Turn the ignition switch to OFF. Ground the auto A/C control module connector with a suitable wire. Turn the ignition switch to ON, and check the operation of intake door actuator. Connector & terminal: (i49) No. 18 - Chassis groundIs the intake door actuator moved to RECIRC?Replace the auto A/C control module.Replace the intake door actuator.

DIAGNOSTIC PROCEDURE CHART

MODE DOOR ACTUATOR

TROUBLE SYMPTOM

Air flow outlet is not changed.

WIRING DIAGRAM

Scheme 15

Scheme 15: MODE DOOR ACTUATOR
StepCheckYesNo
1 CHECK THE POWER SUPPLY OF THE AUTO A/C CONTROL MODULE. Turn the ignition switch to ON. Set the air flow control dial to the VENT position. Press the defroster switch and measure the voltage between the auto A/C control module and the chassis ground when switching from VENT to DEF. Connector & terminal (i49) No. 9 (+) - Chassis ground (-)Is the voltage more than 12 V?Go to step 2.Replace the auto A/C control module.
2 CHECK THE POWER SUPPLY OF THE ACTUATOR. Set the air flow control dial to the VENT position. Press the defroster switch and measure the voltage between the mode door actuator harness connector terminal and the chassis ground when switching from VENT to DEF. Connector & terminal (B77) No. 1 (+) - Chassis ground (-)Is the voltage 7 V or more (at normal temperature)?Go to step 3.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
3 CHECK AUTO A/C CONTROL MODULE SIGNALS. Press the defroster switch. Turn the air flow control dial to VENT and measure the voltage between the auto A/C control module and the chassis ground when switching from DEF to VENT. Connector & terminal (149) No. 8 (+) - Chassis ground (-)Is the voltage more than 12 V?Go to step 4.Replace the auto A/C control module.
4 CHECK THE SIGNALS OF THE ACTUATOR. Press the defroster switch. Turn the air flow control dial to the VENT position and measure the voltage between the mode door actuator harness connector terminal and the chassis ground when switching from DEF to VENT. Connector & terminal (B77) No. 2 (+) - Chassis ground (-)Is the voltage 7 V or more (at normal temperature)?Go to step 5.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
5 CHECK THE ACTUATOR. Turn the ignition switch to OFF. Disconnect the connector from the mode door actuator. Connect the positive terminal (+) of the battery to No. 1 terminal of the mode door actuator, and the negative (-) terminal to No. 2 terminal. Check whether the actuator is running. Connect the negative (-) terminal of the battery to No. 1 and the positive terminal (+) to No. 2 terminal and check whether the actuator is running.Does the motor operate normally?Go to step 6.Replace the mode door actuator.
6 CHECK AUTO A/C CONTROL MODULE SIGNAL VOLTAGE. Turn the ignition switch to ON. Turn the air flow control dial and measure the voltage between auto A/C control module harness connector terminal and chassis ground for each mode. Connector & terminal (i48) No. 4 (+) - Chassis ground (-)Is the voltage approx. 5 V at the HEAT, D/H and DEF positions; and approx. 0 V at the VENT and BI-LEVEL positions?Go to step 9.Go to step 7.
7 CHECK AUTO A/C CONTROL MODULE SIGNAL POWER. Turn the ignition switch to OFF. Disconnect the connector from the mode door actuator. Turn the ignition switch to ON. Measure the voltage between the mode door actuator harness connector terminal and chassis ground. Connector & terminal (B77) No. 5 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 9.Go to step 8.
8 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND MODE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module and mode door actuator. Measure the resistance of the harness between the auto A/C control module and mode door actuator. Connector & terminal (i48) No. 4 - (B77) No. 5Is the resistance less than 1 ohms?Replace the auto A/C control module.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
9 CHECK AUTO A/C CONTROL MODULE SIGNAL VOLTAGE. Turn the ignition switch to ON. Turn the air flow control dial and measure the voltage between auto A/C control module harness connector terminal and chassis ground for each mode. Connector & terminal (i48) No. 12 (+) - Chassis ground (-)Is the voltage approx. 5 V at the VENT position; and approx. 0 V at the BI-LEVEL, HEAT and DEF positions?Go to step 12 .Go to step 10 .
10 CHECK AUTO A/C CONTROL MODULE SIGNAL POWER. Turn the ignition switch to OFF. Disconnect the connector from the mode door actuator. Turn the ignition switch to ON. Measure the voltage between the mode door actuator harness connector and chassis ground. Connector & terminal (B77) No. 6 (+) - Chassis ground (-): (B77) No. 9 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 12 .Go to step 11 .
11 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND MODE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module and mode door actuator. Measure the resistance of the harness between the auto A/C control module and mode door actuator. Connector & terminal (i48) No. 12 - (B77) No. 6: (i48) No. 12 - (B77) No. 9Is the resistance less than 1 ohms?Replace the auto A/C control module.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
12 CHECK AUTO A/C CONTROL MODULE SIGNAL VOLTAGE. Turn the ignition switch to ON. Turn the air flow control dial and measure the voltage between auto A/C control module harness connector and chassis ground for each mode. Connector & terminal (i48) No. 5 (+) - Chassis ground (-)Is the voltage approx. 5 V at the BI-LEVEL and DEF positions; and approx. 0 V at the VENT, HEAT and D/H positions?Go to step 15 .Go to step 13 .
13 CHECK AUTO A/C CONTROL MODULE SIGNAL POWER. Turn the ignition switch to OFF. Disconnect the connector from the mode door actuator. Turn the ignition switch to ON. Measure the voltage between the mode door actuator harness connector terminal and chassis ground. Connector & terminal (B77) No. 4 (+) - Chassis ground (-): (B77) No. 7 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 15 .Go to step 14 .
14 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND MODE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module and mode door actuator. Measure the resistance of the harness between the auto A/C control module and mode door actuator. Connector & terminal (i48) No. S - (B77) No. 4: (i48) No. S - (B77) No. 7Is the resistance less than 1 ohms?Replace the auto A/C control module.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
15 CHECK AUTO A/C CONTROL MODULE SIGNAL VOLTAGE. Turn the ignition switch to ON. Turn the air flow control dial and measure the voltage between auto A/C control module harness connector terminal and chassis ground for each mode. Connector & terminal (i48) No. 13 (+) - Chassis ground (-)Is the voltage approx. 5 V at the VENT, BI-LEVEL and HEAT positions; and approx. 0 V at the D/H and DEF positions?Go to step 19 .Go to step 16 .
16 CHECK AUTO A/C CONTROL MODULE SIGNAL POWER. Turn the ignition switch to OFF. Disconnect the connector from the mode door actuator. Turn the ignition switch to ON. Measure the voltage between mode door actuator. Connector & terminal (B77) No. 8 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 18 .Go to step 17 .
17 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND MODE DOOR ACTUATOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module and mode door actuator. Measure the resistance of the harness between the auto A/C control module and mode door actuator. Connector & terminal (i48) No. 13 - (B77) No. 8Is the resistance less than 1 ohms?Replace the auto A/C control module.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
18 CHECK ACTUATOR GROUND CIRCUIT. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module. Measure the resistance of the harness between the auto A/C control module and mode door actuator. Connector & terminal (i48) No. 16 - (B77) No. 10Is the resistance less than 1 ohmsReplace the mode door actuator.Repair the open circuit of harness between the auto A/C control module and mode door actuator.
19 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

AIR MIX DOOR ACTUATOR

TROUBLE SYMPTOM

Outlet air temperature does not change.

WIRING DIAGRAM

Scheme 16

Scheme 16: AIR MIX DOOR ACTUATOR
StepCheckYesNo
1 CHECK POWER SUPPLY FOR AIR MIX DOOR ACTUATOR PBR. Turn the ignition switch to OFF. Disconnect the air mix door actuator connector. Turn the ignition switch and AUTO switch ON. Measure the voltage between auto A/C control module connector terminals. Connector & terminal (i48) No. 7 (+) - (i48) No. 16 (-)Is the voltage approx. 5 V?Go to step 2.Replace the auto A/C control module.
2 CHECK POWER SUPPLY FOR AIR MIX DOOR ACTUATOR. Measure the voltage between auto A/C control module connector terminal and chassis ground after turning the temperature control dial to maximum COOL position. Connector & terminal (i49) No. 6 (+) - Chassis ground (-)Is the voltage 7 V or more (at normal temperature)?Go to step 3.Replace the auto A/C control module.
3 CHECK POWER SUPPLY FOR AIR MIX DOOR ACTUATOR. Measure the voltage between auto A/C control module connector terminal and chassis ground after turning the temperature control dial to maximum HOT position. Connector & terminal (i49) No. 7 (+) - Chassis ground (-)Is the voltage 7 V or more (at normal temperature)?Go to step 4.Replace the auto A/C control module.
4 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND AIR MIX DOOR ACTUATOR. Turn the A/C and ignition switch to OFF. Disconnect the auto A/C control module connector. Measure the resistance between auto A/C control module and air mix door actuator connector. Connector & terminal (i65) No. 1 - (i49) No. 1: (i65) No. 2 - (i49) No. 7: (i65) No. 3 - (i46) No. 16: (i65) No. 4 - (i48) No. 7: (i65) No. 6 - (i49) No. 6Is the resistance less than 1 ohms?Go to step 5.Repair the open circuit of harness between auto A/C control module and air mix door actuator.
5 CHECK AIR MIX DOOR ACTUATOR PBR SIGNAL. Connect the auto A/C control module and air mix door actuator connector. Turn the ignition switch and AUTO switch ON. Check the voltage between auto A/C control module connector terminals while changing the setting temperature between maximum COOL and maximum HOT. Connector & terminal (i49) No. 1 (+) - (i48) No. 16 (-)Is the voltage 0.5 (Max. HOT) - 4.5 (Max. COOL) V?Go to step 6.Replace the air mix door actuator.
6 CHECK POOR CONTACT. Check poor contact of auto A/C control module and connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

AMBIENT SENSOR

TROUBLE SYMPTOM

  1. Fan speed is not switched when the fan speed control dial is in AUTO position.
  2. Failure related to the ambient sensor is indicated in self-diagnosis. WIRING DIAGRAM

Scheme 17

Scheme 17
StepCheckYesNo
1 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND COMBINATION METER. Turn the ignition switch to OFF. Disconnect the connector from auto A/C control module and the combination meter. Measure the resistance of harness between the auto A/C control module and combination meter. Connector & terminal (i10) No. 30 - (i48) No. 14Is the resistance less than 1 ohms?Go to step 2.Repair the open circuit of the harness between auto A/C control module and combination meter.
2 CHECK AMBIENT SENSOR CIRCUIT. Check the ambient sensor circuit. CHECK OUTSIDE TEMPERATURE INDICATOR INSPECTION, Combination Meter System. >Is the ambient sensor circuit normal?Go to step 3.Repair the ambient sensor circuit.
3 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

IN-VEHICLE SENSOR

TROUBLE SYMPTOM

  1. Blower fan speed, outlet port and inlet port do not change after turning the AUTO switch ON
  2. Failure related to the in-vehicle sensor is indicated in self-diagnosis.

Scheme 18

Scheme 18
StepCheckYesNo
1 CHECK IN-VEHICLE SENSOR. Turn the ignition switch to OFF. Remove the driver side lower cover. Disconnect the connector from in-vehicle sensor. Measure the resistance between connector terminals of in-vehicle sensor. Terminals No. 1-No.2Is the resistance approximately 2.7 kohms at 20°C (68°F)?Go to step 2.Replace the in-vehicle sensor.
2 CHECK INPUT SIGNAL FOR IN-VEHICLE SENSOR. Turn the ignition switch to ON. Measure the voltage between in-vehicle sensor harness connector terminal and chassis ground. Connector & terminal (i55) No. 2 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 5.Go to step 3.
3 CHECK AUTO A/C CONTROL MODULE OUTPUT SIGNAL. Turn the ignition switch to OFF. Pull out the auto A/C control module. Turn the ignition switch to ON. Measure the voltage between connector terminals of auto A/C control module. Connector & terminal (i49) No. 12 (+) - (i48) No. 16 (-)Is the voltage approx. 5 V?Go to step 4.Go to step 6.
4 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND IN-VEHICLE SENSOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module. Measure the resistance of harness between auto A/C control module and in-vehicle sensor. Connector & terminal (i55) No. 2 - (i49) No. 12Is the resistance less than 1 ohms?Go to step 5.Repair the open circuit of the harness between auto A/C control module and in-vehicle sensor.
5 CHECK HARNESS BETWEEN AUTO A/C CONTROL MODULE AND IN-VEHICLE SENSOR. Measure the resistance of harness between auto A/C control module and in-vehicle sensor. Connector & terminal (i55) No. 1 - (i48) No. 16Is the resistance less than 1 ohms?Go to step 6.Repair the open circuit of the harness between auto A/C control module and in-vehicle sensor.
6 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

EVAPORATOR SENSOR

WIRING DIAGRAM

Scheme 19

Scheme 19: EVAPORATOR SENSOR
StepCheckYesNo
1 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 the evaporator sensor. Terminals No. 1 - No.3Is the resistance approximately 2.7 kohms at 20°C (68°F)?Go to step 2.Replace the evaporator sensor.
2 CHECK INPUT SIGNAL FOR EVAPORATOR SENSOR. Turn the ignition switch to ON. Measure the voltage between evaporator sensor harness connector terminal and chassis ground. Connector & terminal (B256) No. 1 (+) - Chassis ground (-)Is the voltage approx. 5 V?Go to step 5.Go to step 3.
3 CHECK AUTO A/C CONTROL MODULE OUTPUT SIGNAL. Turn the ignition switch to OFF. Pull out the auto A/C control module. Turn the ignition switch to ON. Measure the voltage between connector terminals of auto A/C control module. Connector & terminal (i49) No. 2 (+) - (i48) No. 16 (-)Is the voltage approx. 5 V?Go to step 4.Go to step 6.
4 CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND EVAPORATOR SENSOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module. Measure the resistance of harness between auto A/C control module and evaporator sensor. Connector & terminal (B256) No. 1 - (i49) No. 2Is the resistance less than 1 ohms?Go to step 5.Repair the open circuit of harness between auto A/C control module and evaporator sensor.
5 CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND EVAPORATOR SENSOR. Measure the resistance of harness between auto A/C control module and evaporator sensor. Connector & terminal (B256) No. 3 - (i48) No. 16Is the resistance less than 1 ohms?Go to step 6.Repair the open circuit of harness between auto A/C control module and evaporator sensor.
6 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact in the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART

SUNLOAD SENSOR

TROUBLE SYMPTOM

  1. Sensor identifies that sunlight is at maximum. Then, A/C system is controlled to COOL side.
  2. Sensor identifies that sunlight is at minimum. Then, A/C system is controlled to HOT side.

Note. When the sunload sensor is checked indoors or in the shade, an open circuit might be indicated. Always check the sunload sensor at a location exposed to direct sunlight.

WIRING DIAGRAM

Scheme 20

Scheme 20
StepCheckYesNo
1 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?Go to step 3.Go to step 2.
2 CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND SUN-LOAD SENSOR. Turn the ignition switch to OFF. Disconnect the connector from the auto A/C control module. Measure the resistance of the harness between the auto A/C control module and sun-load sensor. Connector & terminal (i51) No. 2 - (i49) No. 3Is the resistance less than 1 ohms?Go to step 5.Repair the harness between auto A/C control module and sunload sensor.
3 CHECK HARNESS CONNECTOR BETWEEN AUTO A/C CONTROL MODULE AND SUN-LOAD SENSOR. Measure the resistance of the harness between the auto A/C control module and sun-load sensor. Connector & terminal (i51) No. 1 - (148) No. 16Is the resistance less than 1 ohms?Go to step 4.Repair the harness between auto A/C control module and sunload sensor.
4 CHECK INPUT VOLTAGE FOR AUTO A/C CONTROL MODULE. Connect the auto A/C control module connector. Turn the ignition switch to ON. Measure the voltage between connector terminals of auto A/C control module. Connector & terminal (i49) No. 3 (+) - (i48) No. 16 (-)Is the voltage approx. 2.5 V?Go to step 5.Replace the sunload sensor.
5 CHECK POOR CONTACT. Check poor contact of auto A/C control module connector.Is there poor contact of the connector?Repair the connector.Replace the auto A/C control module.

DIAGNOSTIC PROCEDURE CHART