A/c-Heater System - Automatic: Other Lexus ES XV10 рестайлинг

SYSTEM CONTROLS

The A/C-heater control assembly consists of a liquid crystal display, a temperature control knob, and various buttons which activate A/C-heater system, set desired temperature, direct discharged air to appropriate outlets, activate rear defogger, control fan speed and check outside air temperature. (Scheme 9)

Scheme 9

HEATER WATER CONTROL VALVE

Disconnect heater water control valve cable, located in heater inlet line near firewall. Turn ignition on. Press A/C button. Set temperature control knob to maximum cool position (counterclockwise). Set heater water control valve to cool position. Install control cable, and secure with clamp. (Scheme 10)

Scheme 10

Indicator Check

1. While pressing and holding AUTO and F/R switches simultaneously, turn ignition on. Indicators will flash and tone will sound as a check. Press OFF button to cancel indicator check. After indicator check is complete, system will enter self-diagnostic mode. Stored trouble codes will appear in sequence on temperature display panel. See «AUTOMATIC A/C-HEATER SYSTEM TROUBLE CODES»(ref-36442-S27027308192001010900000) table.
2. Press fan (down) button to display codes one at a time. If tone sounds when code is displayed, problem causing code currently exists. If tone does not sound when code is displayed, associated problem is past history and does not currently exist. Press OFF button to exit self-diagnostics.

AUTOMATIC A/C-HEATER SYSTEM TROUBLE CODES

CLEARING CODES

Remove ECU-B fuse from fuse block under left side of instrument panel for 10 seconds or longer. After reinstalling fuse, ensure only normal code (Code 00) appears.

ACTUATOR CHECK

1. Perform INDICATOR CHECK under «RETRIEVING CODES»(ref-36442-S20038649102001010900000). When system enters self-diagnostic mode, press F/R switch. Every mode door, motor, and relay will operate at one-second intervals. Press fan (down) button to display codes one at a time and to step through checks one at a time.
2. Check airflow and temperature by hand. Tone will sound each time display code changes. Each code is associated with a system operating condition. (Scheme 11) Press OFF button to cancel actuator check mode.

Scheme 11

CODE 11 IN-VEHICLE TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TR (Green/Yellow wire) and SG (White/ Red wire) at A/C control assembly harness connector. (Scheme 12)
2. Measure voltage while heating sensor. See «IN-VEHICLE (ROOM) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36442-S31107498092001010900000) table. IN-VEHICLE (ROOM) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS Sensor Temperature °F (°C) (1) Volts 77 (25) 1.8-2.2 104 (40) 1.2-1.6 (1) As temperature increases, voltage should gradually decrease.
3. If voltage is not as specified, test in-vehicle (room) sensor. See «IN-VEHICLE TEMPERATURE SENSOR»(ref-36442-S41347112962001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it is defective.
4. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair harness and connectors as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

Scheme 12

CODE 12 - OUTSIDE TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TAM (Black/Red wire) and SG (White/ Red wire) at A/C control assembly harness connector. (Scheme 12)
2. Measure voltage while heating outside (ambient) temperature sensor. See «OUTSIDE (AMBIENT) TEMPERATURE SENSOR CIRCUIT»(ref-36442-S31591125232001010900000) VOLTAGE SPECIFICATIONS table. OUTSIDE (AMBIENT) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS Sensor Temperature °F (°C) (1) Volts 77 (25) 1.35-1.75 104 (40) 0.85-1.25 (1) As temperature increases, voltage should gradually decrease.
3. If voltage is not as specified, test sensor. See «OUTSIDE»(ref-36442-S42920625972001010900000) TEMPERATURE SENSOR under TESTING. If sensor is okay, go to next step. Replace sensor if it is defective.
4. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair harness and connectors as necessary. If wiring harness and connectors are okay, temporarily substitute a known good A/C control assembly. Retest system.

CODE 13 - EVAPORATOR TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TE (Blue/White wire) and SG (White/Red wire) at A/C control assembly harness connector. (Scheme 12)
2. Measure evaporator temperature sensor voltage at the temperatures specified. See «EVAPORATOR TEMPERATURE SENSOR CIRCUIT»(ref-36442-S29128803802001010900000) VOLTAGE SPECIFICATIONS table. EVAPORATOR TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS Sensor Temperature °F (°C) (1) Volts 32 (0) 2.0-2.4 59 (15) 1.4-1.8 (1) As temperature increases, voltage should gradually decrease.
3. If voltage is not as specified, test evaporator temperature sensor. See «EVAPORATOR TEMPERATURE SENSOR»(ref-36442-S02480866132001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it is defective.
4. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair harness and connectors as necessary. If wiring harness and connectors are okay, temporarily substitute a known good A/C control assembly. Retest system.

CODE 14 - WATER TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TW (Yellow/Black wire) and SG (White/ Red wire) at A/C control assembly harness connector. (Scheme 12) Measure sensor voltage. See «WATER (ENGINE COOLANT) TEMPERATURE SENSOR»(ref-36442-S10190045562001010900000) CIRCUIT VOLTAGE SPECS table. WATER (ENGINE COOLANT) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECS Sensor Temperature °F (°C) (1) Volts 32 (0) 2.8-3.2 104 (40) 1.8-2.2 158 (70) 0.9-1.3 (1) As temperature increases, voltage should gradually decrease.
2. If voltage is not as specified, test water (engine coolant) temperature sensor. See «WATER TEMPERATURE SENSOR»(ref-36442-S00371126302001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it is defective.
3. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

CODE 21 - SOLAR SENSOR CIRCUIT

Note. If testing is done in a dark area, Code 21 may occur even though system is normal. Shine a light at solar sensor and recheck for Code 21.

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals S5 (Blue wire) and TS (White wire) at A/C control assembly harness connector. (Scheme 12) Measure sensor voltage. See «SOLAR SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36442-S38083858732001010900000) table. SOLAR SENSOR CIRCUIT VOLTAGE SPECIFICATIONS Condition (1) Volts Sensor Subjected To Bright Light Less Than 4.0 Sensor Covered By Cloth 4.0-4.5 (1) As light intensity decreases, voltage should increase.
2. If voltage is not as specified, test solar sensor. See «SOLAR SENSOR»(ref-36442-S15075895782001010900000) under TESTING. If sensor is okay, go to next step. Replace sensor if it is defective.
3. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

CODE 22 - COMPRESSOR LOCK SENSOR CIRCUIT

1. Ensure drive belt is installed properly, and belt tension is correct. Start engine. Turn blower and A/C on. Observe compressor. If compressor locks during operation, repair compressor. If compressor does not lock during operation, test compressor lock sensor. See «COMPRESSOR LOCK SENSOR»(ref-36442-S29645824402001010900000) under TESTING.
2. Replace compressor lock sensor if it is defective. If sensor is okay, inspect wiring harness and connectors between sensor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

CODE 23 - PRESSURE SWITCH CIRCUIT

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Install manifold gauge set. Turn ignition on. Backprobe terminal PSW (Red/Blue wire) at A/C control assembly harness connector and ground. (Scheme 12)
2. Start engine. Turn A/C on. Pressure switch operation should be as specified in illustration. (Scheme 13) If pressure switch operation is not as specified, go to next step. If pressure switch operation is as specified, circuit is okay.
3. Unplug pressure switch connector, located beneath battery. Test for continuity between switch terminals at refrigerant pressures specified. (Scheme 14) Replace pressure switch if operation is not as specified. If switch is okay, inspect wiring harness and connectors between switch and A/C control assembly. If wiring harness and connectors are okay, substitute known good A/C control assembly. Retest system.

Scheme 13

Scheme 14

CODE 31 OR 41 - AIR MIX DOOR POSITION SENSOR CIRCUIT

Note. For Code 41, see CODE 41 - AIR MIX SERVOMOTOR CIRCUIT for additional trouble shooting procedures.

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TP (Black/Yellow wire) and SG (White/ Red wire) at A/C control assembly harness connector. (Scheme 12)
2. Measure sensor voltage while changing set temperature to activate air mix door. See «AIR MIX DOOR POSITION SENSOR CIRCUIT»(ref-36442-S06251684582001010900000) VOLTAGE table. AIR MIX DOOR POSITION SENSOR CIRCUIT VOLTAGE Set Temperature (1) Volts Maximum Cool 3.5-4.5 Maximum Hot 0.5-1.8 (1) As set temperature increases, voltage should gradually decrease.
3. If voltage is not as specified, test air mix servomotor. See «AIR MIX SERVOMOTOR»(ref-36442-S01695335112001010900000) under TESTING. If servomotor is okay, go to next step. Replace servomotor if it is defective.
4. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

CODE 32 OR 42 - AIR INLET DOOR POSITION SENSOR CIRCUIT

Note. For Code 42, see CODE 42 - AIR INLET SERVOMOTOR CIRCUIT for additional trouble shooting procedures.

1. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals TPI (Blue/Yellow wire) and SG (White/ Red wire) at A/C control assembly harness connector. (Scheme 12)
2. Measure sensor voltage while alternately pressing fresh air and recirculated air buttons to activate air inlet door. See «AIR INLET DOOR POSITION CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36442-S25463959882001010900000) table. AIR INLET DOOR POSITION CIRCUIT VOLTAGE SPECIFICATIONS Switch Pressed (1) Volts Recirculated Air 3.5-4.5 Fresh Air 0.5-1.8 (1) As door moves from recirculated air position toward fresh air position, voltage should gradually decrease.
3. If voltage is not as specified, test air inlet servomotor. See «AIR INLET SERVOMOTOR»(ref-36442-S35626346502001010900000) under TESTING. If servomotor is okay, go to next step. Replace servomotor if it is defective.
4. Inspect wiring harness and connectors between sensor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, temporarily substitute known good A/C control assembly. Retest system.

CODE 41 - AIR MIX SERVOMOTOR CIRCUIT

Note. See CODE 31 OR 41 - AIR MIX DOOR POSITION SENSOR CIRCUIT for additional trouble shooting procedures.

1. Warm engine to normal operating temperature. Perform «RETRIEVING CODES»(ref-36442-S20038649102001010900000) . After system enters self-diagnostic mode, perform «ACTUATOR CHECK»(ref-36442-S02002773592001010900000) .
2. Press fan (down) button to enter step mode and display codes. See «AIR MIX DOOR AIRFLOW»(ref-36442-S12894618712001010900000) table. Air mix door operation should be as specified.
3. If air mix door functions as specified, circuit is okay. If air mix door does not function as specified, see AIR MIX SERVOMOTOR FUNCTIONAL CHECK.

AIR MIX DOOR AIRFLOW

Air Mix Servomotor Functional Check

1. Remove air mix servomotor. See «AIR MIX SERVOMOTOR»(ref-36442-S01695335112001010900000) under REMOVAL & INSTALLATION. Unplug air mix servomotor connector.
2. Apply battery voltage to servomotor connector terminal No. 1 (Light Green wire). (Scheme 15) Connect terminal No. 2 (Brown/Yellow wire) to ground. Air mix servomotor lever should move to cool position. Transpose battery and ground leads. Servomotor lever should move to hot position.
3. Replace air mix servomotor if it does not function as specified. If operation is as specified, inspect wiring harness and connectors between servomotor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, substitute known good A/C control assembly. Retest system.

Scheme 15

CODE 42 - AIR INLET SERVOMOTOR CIRCUIT

Note. See CODE 32 OR 42 - AIR INLET DOOR POSITION SENSOR CIRCUIT for additional trouble shooting procedures.

1. Remove glove box. Perform «RETRIEVING CODES»(ref-36442-S20038649102001010900000) . After system enters self-diagnostic mode, perform «ACTUATOR CHECK»(ref-36442-S02002773592001010900000) .
2. Press fan (down) button to enter step mode and display codes. See «AIR INLET DOOR AIRFLOW»(ref-36442-S07002263452001010900000) table. Air inlet door operation should be as specified. AIR INLET DOOR AIRFLOW Code Door Position 20-22 Fresh Air 23 Fresh/Recirculated Air 24-29 Recirculated Air
3. If air inlet door functions as specified, circuit is okay. If air inlet door does not function as specified, test air inlet servomotor. See AIR INLET SERVOMOTOR FUNCTIONAL TEST.

Air Inlet Servomotor Functional Check

1. Remove air inlet servomotor. See «AIR INLET SERVOMOTOR»(ref-36442-S35626346502001010900000) under REMOVAL & INSTALLATION. Unplug air inlet servomotor connector.
2. Connect battery voltage to air inlet servomotor connector terminal No. 2 (Red wire). (Scheme 16) Connect terminal No. 1 (Red/Blue wire) to ground. Air inlet servomotor lever should move to recirculated air position (REC). Transpose battery and ground leads. Air inlet servomotor lever should move to fresh air position (FRS).
3. Replace air inlet servomotor if it does not operate as specified. If servomotor operates correctly, inspect wiring harness and connectors between servomotor and A/C control assembly. Repair as necessary. If wiring harness and connectors are okay, substitute known good A/C control assembly. Retest system.

Scheme 16

Engine Coolant Temperature Sensor

Remove engine coolant temperature sensor, located at upper left of engine. Heat sensor to 176°F (80°C). Measure resistance between sensor terminals. If resistance is not 1480-1580 ohms, replace sensor.

Cooling Fan Electronic Control Unit

1. Unplug Cooling Fan Electronic Control Unit (ECU) connector, located to right of glove box. Check for battery voltage between ECU connector terminal No. 1 and ground. (Scheme 17) Battery voltage should exist.
2. Turn ignition off. Measure resistance between specified harness connector terminals. See «ECU CIRCUIT RESISTANCE SPECIFICATIONS»(ref-36442-S30520758872001010900000) table. If resistance is as specified, temporarily substitute known good cooling fan ECU and retest.

ECU CIRCUIT RESISTANCE SPECIFICATIONS

Scheme 17

Pressure Switch

For pressure switch testing procedures, see CODE 23 PRESSURE SWITCH CIRCUIT under TROUBLE SHOOTING.

Solenoid Valve

Unplug solenoid valve connector, located at right rear of engine compartment. Measure resistance between connector terminals. If resistance is not 7.6-8.0 ohms at 77°F (80°C), replace solenoid valve.

ACCESSORY POWER CIRCUIT

1. Turn ignition on. Inspect CIG/RADIO fuse, located under left side of instrument panel. If fuse is okay, go to next step. If fuse is blown, correct cause and replace fuse.
2. Turn ignition off. Remove console upper panel. Remove A/C control assembly, leaving harness connectors attached. Turn ignition on. Backprobe A/C control assembly 8-pin connector between terminal ACC (Blue/Red wire) and body ground. (Scheme 12) If battery voltage does not exist, repair Blue/Red wire between connector and CIG/RADIO fuse.

AIR INLET SERVOMOTOR

1. Unplug air inlet servomotor connector. See «AIR INLET»(ref-36442-S35626346502001010900000) SERVOMOTOR under REMOVAL & INSTALLATION. Measure resistance between servomotor connector terminals No. 4 and 5. (Scheme 16) If resistance is 4800-7200 ohms, go to next step. If resistance is not as specified, replace air inlet servomotor.
2. Connect ohmmeter between terminals No. 3 and 4. Connect battery voltage to terminal No. 2. Connect terminal No. 1 to ground. Transpose battery and ground leads. Resistance should be as specified for each door position. See «AIR INLET DOOR POSITION RESISTANCE»(ref-36442-S24674526472001010900000) SPECIFICATIONS table.

AIR INLET DOOR POSITION RESISTANCE SPECIFICATIONS

AIR MIX SERVOMOTOR

1. Remove air mix servomotor. See «AIR MIX SERVOMOTOR»(ref-36442-S01695335112001010900000) under REMOVAL & INSTALLATION. Unplug air mix servomotor connector. Measure resistance between servomotor connector terminals No. 4 (Yellow wire) and No. 5 (Brown/Black wire). (Scheme 18) If resistance is 4800-7200 ohms, go to next step. If resistance is not as specified, replace air mix servomotor.
2. Connect ohmmeter between servomotor terminals No. 3 (Violet/Red wire) and No. 5 (Brown/Black wire). Connect air mix servomotor terminal No. 1 (Light Green wire) to battery voltage. (Scheme 15) Connect terminal No. 2 (Brown/Yellow wire) to ground. Transpose battery and ground leads. Resistance should be as specified for each door position. See «AIR MIX DOOR POSITION RESISTANCE»(ref-36442-S04883879512001010900000) SPECIFICATIONS table.

AIR MIX DOOR POSITION RESISTANCE SPECIFICATIONS

Scheme 18

AIR OUTLET SERVOMOTOR CIRCUIT

1. Warm engine to normal operating temperature. Perform «RETRIEVING CODES»(ref-36442-S20038649102001010900000) under TROUBLE SHOOTING. After system enters self-diagnostic mode, perform «ACTUATOR CHECK»(ref-36442-S02002773592001010900000) under TROUBLE SHOOTING.
2. Press fan (down) button to enter step mode and display codes. See «AIR OUTLET DOOR AIRFLOW»(ref-36442-S30856760992001010900000) table. Air outlet door operation should be as specified.
3. If air outlet door servomotor functions as specified, circuit is okay. If air outlet door does not function as specified, test air outlet servomotor. See AIR OUTLET SERVOMOTOR FUNCTIONAL TEST.

AIR OUTLET DOOR AIRFLOW

BACK-UP POWER CIRCUIT

1. Turn ignition off. Inspect ECU-B fuse at fuse block under left side of instrument panel. If fuse is okay, go next step. If fuse is blown, correct cause and replace fuse.
2. Remove A/C control assembly, leaving harness connectors attached. Turn ignition on. Backprobe A/C control assembly 8-pin connector terminal +B (Blue/Yellow wire) and body ground. (Scheme 12) If battery voltage does not exist, repair Blue/Yellow wire between connector and ECU-B fuse.

BLOWER MOTOR CIRCUIT

1. Turn ignition off. Remove blower motor. See «BLOWER MOTOR»(ref-36442-S00031958352001010900000) under REMOVAL & INSTALLATION. Connect battery voltage to terminal No. 2 (Black wire) of blower motor. Connect terminal No. 1 (Red wire on 1995; Black/White wire on 1996) to ground. If blower motor runs smoothly, go to next step. Replace blower motor if it does not run smoothly.
2. Inspect wiring between blower motor and battery, and between blower motor and ground. Repair wiring as necessary.

Scheme 19

1. Turn ignition on. Inspect GAUGE fuse at fuse block under left side of instrument panel. If fuse is okay, go next step. If fuse is blown, correct cause and replace fuse.
2. Turn ignition off. Remove A/C control assembly, leaving harness connectors attached. See «A/C CONTROL ASSEMBLY»(ref-36442-S23866793742001010900000) under REMOVAL & INSTALLATION. Start engine and run at idle. Backprobe A/C control assembly connector terminal MGC (Blue/Yellow wire) and body ground. (Scheme 12)
3. Press AUTO button. Voltmeter should indicate less than one volt. Press OFF button. Voltmeter should indicate battery voltage. If operation is as specified, go to next step. If operation is as not as specified, go to step 8).
4. Remove compressor clutch relay from relay box No. 5, located at left side of engine compartment, toward rear. Measure resistance between terminals No. 1 and 2. (Scheme 19) Resistance should be 62.5-90.9 ohms. Test for continuity between terminals No. 3 and 5. Continuity should not exist.
5. Connect battery voltage to terminal No. 1 of relay. Connect terminal No. 2 to ground. Test for continuity between terminals No. 3 and 5. Continuity should exist. If relay operates as specified, go to next step. Replace relay if it does not operate as specified.
6. Unplug connector from compressor clutch. Connect battery voltage to compressor clutch connector terminal No. 4 (Blue/Black wire). If clutch engages, go to next step. If clutch does not engage, repair or replace compressor clutch.
7. Inspect wiring and connectors associated with compressor relay and compressor. Repair or replace wiring and connectors as necessary. If wiring and connectors are okay, go to next step.
8. Turn ignition off. Unplug 23-pin connector from A/C control assembly. Turn ignition on. Check for voltage at harness connector terminal AC1 (Black/Yellow wire). If battery voltage exists, go to next step. If battery voltage does not exist, substitute known good Engine Control Module (ECM). Retest system.
9. Connect wiring to A/C control assembly. Backprobe terminal AC1 (Black/Yellow wire) of 23-pin connector and ground. (Scheme 12) Start engine. Press AUTO button. Cycle A/C system on and off by pressing AUTO button. With compressor clutch engaged, meter should indicate less than one volt. With compressor clutch disengaged, meter should indicate battery voltage. If voltages are as specified, go to next step. If voltages are not as specified, substitute known good A/C control assembly. Retest system.
10. Backprobe terminal ACT (Light Green/Red wire) of 23-pin connector and ground. Start engine. Press AUTO button. Cycle A/C system on and off by pressing A/C button. With A/C system off, meter should indicate less than 1.5 volts. With A/C system on, meter should indicate battery voltage. If voltages are not as specified, go to next step. If voltages are as specified, substitute known good A/C control assembly. Retest system.
11. Inspect wiring and connectors associated with A/C control assembly and ECM. Repair as necessary. If wiring harnesses and connectors are okay, go to next step.
12. Turn ignition off. Remove glove box. Unplug connectors from ECM. Turn ignition on. Press AUTO button to turn system on. Measure voltage between terminal ACT (Light Green/Red wire) on Engine Control Module (ECM) and ground. (Scheme 20)
13. With A/C switch on, 9-14 volts should exist. With A/C switch off, 0-2 volts should exist. If voltage is not as specified, temporarily substitute known good A/C control assembly, and retest. If voltage is as specified, temporarily substitute known good ECM. Retest system.

Scheme 20

COMPRESSOR LOCK SENSOR

Unplug compressor lock sensor connector, located at compressor. Measure resistance between terminals No. 1 and 2 of sensor at temperature specified. (Scheme 21) Replace sensor if resistance is 65-125 ohms at 68°F (20°C).

Scheme 21

EVAPORATOR TEMPERATURE SENSOR

Remove evaporator temperature sensor, located at evaporator. Measure sensor resistance at the temperatures specified. See EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace sensor.

EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

EXTRA-HIGH RELAY CIRCUIT

1. Perform «RETRIEVING CODES»(ref-36442-S20038649102001010900000) under TROUBLE SHOOTING. After system enters self-diagnostic mode, perform «ACTUATOR CHECK»(ref-36442-S02002773592001010900000) under TROUBLE SHOOTING. Press fan (down) button to enter step mode and display codes. See «BLOWER SPEED»(ref-36442-S34591101812001010900000) table. If blower speed does not change as specified, go to next step. If blower speed is as specified, circuit is okay. BLOWER SPEED Code Blower Speed 21 Low 22-28 Medium 29 High
2. Remove extra-high relay, located on evaporator assembly. Measure resistance between relay terminals No. 3 and 4. (Scheme 22) Continuity should exist through relay coil. Test for continuity between terminals No. 1 and 2. Continuity should not exist.
3. Connect battery voltage to terminal No. 3. Connect terminal No. 4 to ground. Test for continuity between terminals No. 1 and 2. Continuity should exist. If relay operates as specified, go to next step. Replace relay if it does not operate as specified.
4. Inspect wiring harness and connectors between A/C control assembly and extra-high relay, and between extra-high relay and battery. Repair as necessary. If wiring harnesses and connectors are okay, substitute known good A/C control assembly. Retest system.

Scheme 22

HEATER MAIN RELAY CIRCUIT

1. Turn ignition on. Inspect GAUGE fuse at fuse block under left side of instrument panel. If fuse is okay, go next step. If fuse is blown, correct cause and replace fuse.
2. Remove A/C control assembly, leaving harness connectors attached. Turn ignition off. Check for voltage between A/C control assembly 23-pin connector terminal HR (Blue/White wire) and body ground. (Scheme 12) If battery voltage does not exist, go to next step. If battery voltage exists, repair short to voltage on Blue/White wire between connector and heater main relay.
3. Turn ignition on. Check for voltage between A/C control assembly 23-pin connector terminal HR (Blue/White wire) and body ground. If battery voltage does not exist, go to next step. If battery voltage exists, circuit is okay.
4. Remove heater main relay, located behind glove box, on right side. Test for continuity between terminals No. 1 and 4. (Scheme 23) Continuity should not exist. Test for continuity between terminals No. 2 and 4. Continuity should exist. Measure resistance between terminals No. 3 and 5. Resistance should be 62.5-90.9 ohms.
5. Connect battery voltage to terminal No. 3, and connect terminal No. 5 to ground. Test for continuity between terminals No. 1 and 2. Continuity should exist. Test for continuity between terminals No. 2 and 4. Continuity should not exist. Replace relay if it does not operate as specified. If relay is okay, repair wiring between 8-pin connector and battery.

Scheme 23

IGNITION POWER & GROUND CIRCUITS

1. Turn ignition on. Inspect GAUGE fuse at fuse block under left side of instrument panel. If fuse is okay, go next step. If fuse is blown, correct cause and replace fuse.
2. Remove console upper panel. Remove A/C control assembly, leaving harness connectors attached. Turn ignition on. Using DVOM, backprobe 8-pin connector terminals IG+ (Red/Blue wire) and GND (White/Black wire). (Scheme 12) If battery voltage does not exist, go to next step. If battery voltage exists, circuit is okay.
3. Turn ignition off. Unplug 8-pin connector from A/C control assembly. Inspect Red/Blue wire between connector IG+ terminal and GAUGE fuse for continuity or short to ground. Repair wire as necessary. If wire is okay, go to next step.
4. Measure resistance between GND terminal of connector (White/Black wire) and ground. If resistance is less than one ohm, wire is okay. Repair open White/Black wire to ground if resistance is not less than one ohm.

IN-VEHICLE TEMPERATURE SENSOR

Remove in-vehicle temperature sensor. see scheme 1 Measure sensor resistance while heating sensor. See IN-VEHICLE TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace sensor.

IN-VEHICLE TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

OUTSIDE TEMPERATURE SENSOR

1. Unplug outside temperature sensor, located behind grille. Measure the sensor resistance while heating the sensor. See «OUTSIDE TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS»(ref-36442-S00820274332001010900000) table.
2. If resistance is not as specified, replace sensor. If resistance is within specification, check wiring harness and connectors between sensor and A/C control assembly. Repair harness and connectors as necessary. If wiring harness and connectors are okay, substitute known good A/C control assembly. Retest system.

OUTSIDE TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

POWER TRANSISTOR CIRCUIT

1. Remove power transistor. See «POWER TRANSISTOR»(ref-36442-S15947584852001010900000) under REMOVAL & INSTALLATION. Connect battery voltage, through a 12-volt, 3.4-watt bulb, to power transistor terminal No. 1. Connect terminal No. 4 to ground. (Scheme 24)
2. Connect a second 12-volt, 3.4-watt test light between battery voltage and transistor terminal No. 2. If test light glows, go to next step. If test light does not glow, replace power transistor. Disconnect battery leads.
3. Measure resistance between terminals No. 2 and 4. If resistance is 2000-2400 ohms, power transistor is okay. Replace power transistor if resistance is not as specified.

Scheme 24

SOLAR SENSOR

Remove solar sensor from top of instrument panel. Unplug harness connector. Cover sensor with cloth. Measure resistance between sensor terminals. Remove cloth. Subject sensor to bright light. Measure resistance between sensor terminals. See SOLAR SENSOR RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace sensor.

SOLAR SENSOR RESISTANCE SPECIFICATIONS

WATER TEMPERATURE SENSOR

Remove water (engine coolant) temperature sensor, located at heater core. Place sensor and thermometer in water. Measure resistance between sensor terminals as water is heated. See WATER TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS table. If resistance is not as specified, replace water temperature sensor.

WATER TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS