A/c-Heater System: Other Lexus ES XV20

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 8)

Scheme 8

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 9)

Scheme 9

Indicator Check

1. While pressing and holding AUTO and fresh/recirculated air switches simultaneously, turn ignition on. (Scheme 8) 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»(ref-36654-S07821853472001010900000) CODES 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-36654-S02698604092001010900000). When system enters self-diagnostic mode, press fresh/recirculated air switch. Every mode damper, 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 10) Press OFF button to cancel actuator check mode.

Scheme 10

CODE 11: IN-VEHICLE TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-4 (Green/Yellow wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11)
2. Measure the voltage while heating the sensor. See «IN-VEHICLE (ROOM) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36654-S37255549502001010900000) 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) temperature sensor. See «IN-VEHICLE TEMPERATURE SENSOR»(ref-36654-S21030470872001010900000) 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 11

CODE 12: AMBIENT TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-3 (Yellow wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11)
2. Measure voltage while heating outside (ambient) temperature sensor. See «AMBIENT (OUTSIDE) TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36654-S36185314592001010900000) table. AMBIENT (OUTSIDE) 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 procedures in «AMBIENT TEMPERATURE SENSOR»(ref-36654-S18210360562001010900000) 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-6 (Blue/White wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11)
2. Measure evaporator temperature sensor voltage at the temperatures specified. See «EVAPORATOR TEMPERATURE SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36654-S06493484352001010900000) 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-36654-S16973710372001010900000) 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: ENGINE COOLANT TEMPERATURE SENSOR CIRCUIT

1. Remove A/C control assembly, leaving harness connectors connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-14 (Violet wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11) Measure sensor voltage. See ENGINE COOLANT (WATER) TEMP. SENSOR CIRCUIT VOLTAGE SPECIFICATIONS table. ENGINE COOLANT (WATER) TEMP. SENSOR CIRCUIT VOLTAGE SPECIFICATIONS 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 «ENGINE COOLANT TEMPERATURE SENSOR»(ref-36654-S27696932522001010900000) 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A14-11 (Blue wire) and A15-5 (White wire) at A/C control assembly harness connector. (Scheme 11) Measure sensor voltage. See «SOLAR SENSOR CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36654-S15716254892001010900000) 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-36654-S42779025202001010900000) 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-36654-S03955469702001010900000) 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Install manifold gauge set. Turn ignition on. Backprobe terminal A15-9 (Red/Blue wire) at A/C control assembly harness connector and ground. (Scheme 11)
2. Start engine. Turn A/C on. Pressure switch operation should be as specified. (Scheme 12) 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 13) 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 12

Scheme 13

CODE 31 OR 41: AIR MIX DAMPER 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-8 (Black/Yellow wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11)
2. Measure sensor voltage while changing set temperature to activate air mix damper. See «AIR MIX DAMPER POSITION SENSOR CIRCUIT»(ref-36654-S07429022782001010900000) VOLTAGE table. AIR MIX DAMPER 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 TESTING»(ref-36654-S38225455162001010900000). 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 DAMPER 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Turn ignition on. Backprobe terminals A15-7 (Pink/Blue wire) and A14-1 (White/Red wire) at A/C control assembly harness connector. (Scheme 11)
2. Measure sensor voltage while alternately pressing fresh air and recirculated air buttons to activate air inlet damper. See «AIR INLET DAMPER POSITION CIRCUIT VOLTAGE SPECIFICATIONS»(ref-36654-S26635430642001010900000) table. AIR INLET DAMPER POSITION CIRCUIT VOLTAGE SPECIFICATIONS Switch Pressed (1) Volts Recirculated Air 3.5-4.5 Fresh Air 0.5-1.8 (1) As damper 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 TESTING»(ref-36654-S27140613982001010900000). 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 DAMPER POSITION SENSOR CIRCUIT for additional trouble shooting procedures.

1. Warm engine to normal operating temperature. Perform «RETRIEVING CODES»(ref-36654-S02698604092001010900000) . After system enters self-diagnostic mode, perform «ACTUATOR CHECK»(ref-36654-S19704395512001010900000) .
2. Press DEF switch and check operation of air mix damper and blower condition. See «AIR MIX DAMPER AIRFLOW»(ref-36654-S39591447332001010900000) table. Air mix damper operation should be as specified.
3. If air mix damper functions as specified, circuit is okay. If air mix damper does not function as specified, see procedures in AIR MIX SERVOMOTOR FUNCTIONAL CHECK.

AIR MIX DAMPER AIRFLOW

Air Mix Servomotor Functional Check

1. Remove air mix servomotor. See «MIX SERVOMOTOR»(ref-36654-S03230231762001010900000) under REMOVAL & INSTALLATION. Unplug air mix servomotor connector.
2. Apply battery voltage to servomotor connector terminal No. 1 (Pink wire). (Scheme 14) Connect terminal No. 2 (Green/Red 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 14

CODE 42: AIR INLET SERVOMOTOR CIRCUIT

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

1. Remove glove box. Perform «RETRIEVING CODES»(ref-36654-S02698604092001010900000) . After system enters self-diagnostic mode, perform ACTUATOR CHECK.
2. Press DEF button to enter step mode and display codes. See AIR INLET DAMPER AIRFLOW table. Air inlet damper operation should be as specified. AIR INLET DAMPER AIRFLOW Code Door Position 0-2 Fresh Air 3 Fresh/Recirculated Air 4-9 Recirculated Air
3. If air inlet damper functions as specified, circuit is okay. If air inlet damper does not function as specified, test air inlet servomotor. See AIR INLET SERVOMOTOR FUNCTIONAL CHECK.

Air Inlet Servomotor Functional Check

1. Remove air inlet servomotor. See «INLET SERVOMOTOR»(ref-36654-S17958985862001010900000) under REMOVAL & INSTALLATION. Unplug air inlet servomotor connector.
2. Connect battery voltage to air inlet servomotor connector terminal No. 2 (Red wire). (Scheme 15) Connect terminal No. 1 (Blue/Yellow wire) to ground. Air inlet servomotor lever should move to recirculated air (REC) position. Transpose battery and ground leads. Air inlet servomotor lever should move to fresh air (FRS) position.
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 15

COOLING FAN RELAYS

Note. Relays are located in relay box, located in left side of engine compartment. Relays are identified on relay box lid.

Cooling Fan Relay No. 1

Ensure continuity is present between relay terminals No. 1 and 2, and between terminals No. 3 and 4. Apply battery voltage between relay terminals No. 1 and 2. Continuity should be present between relay terminals No. 3 and 4. (Scheme 16)

Cooling Fan Relay No. 2

Ensure continuity is present between relay terminals No. 1 and 2, and between terminals No. 3 and 4. Apply battery voltage between relay terminals No. 1 and 2. Continuity should be present between relay terminals No. 3 and 5. (Scheme 16)

Cooling Fan Relay No. 3

Ensure continuity is present between relay terminals No. 1 and 2. Apply battery voltage between relay terminals No. 1 and 2. Continuity should be present between relay terminals No. 3 and 5. (Scheme 16)- (Scheme 18).

Scheme 16

Scheme 17

Scheme 18

ACCESSORY POWER CIRCUIT

1. Turn ignition on. Inspect HEATER 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 ashtray. Remove A/C control assembly, leaving harness connectors connected. Turn ignition on. Backprobe A/C control assembly connector between ground and terminal A14-26 (Blue/Black wire). (Scheme 11) If battery voltage does not exist, repair Blue/Black wire between connector and HEATER fuse.

AIR OUTLET SERVOMOTOR CIRCUIT

1. Warm engine to normal operating temperature. Perform «RETRIEVING CODES»(ref-36654-S02698604092001010900000) under TROUBLE SHOOTING. After system enters self-diagnostic mode, perform ACTUATOR CHECK.
2. Press fan (down) button to enter step mode and display codes. See «AIR OUTLET DAMPER AIRFLOW»(ref-36654-S28972754882001010900000) table. Air outlet damper operation should be as specified.
3. If air outlet damper servomotor functions as specified, circuit is okay. If air outlet damper does not function as specified, test air outlet servomotor. See AIR OUTLET SERVOMOTOR FUNCTIONAL TEST.

AIR OUTLET DAMPER AIRFLOW

AMBIENT TEMPERATURE SENSOR

1. Unplug temperature sensor, located behind grille. Measure sensor resistance while heating sensor. See «AMBIENT TEMPERATURE SENSOR»(ref-36654-S33863641982001010900000) RESISTANCE SPECIFICATIONS 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.

AMBIENT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

BACK-UP POWER CIRCUIT

1. Turn ignition off. Inspect ECU-B fuse at fuse block at left side of engine compartment. 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 connected. Turn ignition on. Backprobe A/C control assembly connector terminal A14-13 (White/Black wire) and ground. (Scheme 11) If battery voltage does not exist, repair White/Black wire between connector and ECU-B fuse.

BLOWER MOTOR CIRCUIT

1. Turn ignition off. Remove blower motor. See procedures in «BLOWER MOTOR REMOVAL & INSTALLATION»(ref-36654-S09864913542001010900000) under REMOVAL & INSTALLATION. Connect battery voltage to terminal No. 2 (Black wire) of blower motor. Connect terminal No. 1 (Black/White wire) 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 HEATER 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 connected. See «A/C CONTROL ASSEMBLY»(ref-36654-S39037538362001010900000) under REMOVAL & INSTALLATION. Start and run engine at idle. Backprobe A/C control assembly connector terminal A15-2 (Blue/Yellow wire) and ground. (Scheme 11)
3. Press ON 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 (Black/White 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 connector A15 from A/C control assembly. (Scheme 11) Turn ignition on. Check for voltage at harness connector terminal A15-13 (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. Turn ignition off and reconnect wiring to A/C control assembly. Using a DVOM, backprobe between terminal A15-13 (Black/Yellow wire) of A/C control assembly connector and ground. (Scheme 11) Start engine. Press AUTO button. Cycle A/C system on and off by pressing AUTO button. With compressor clutch engaged, voltmeter should indicate less than one volt. With compressor clutch disengaged, voltmeter 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. Using a DVOM, backprobe between terminal A15-10 (Light Green/Black wire) of A/C control assembly 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, voltmeter should indicate less than one volt. With A/C system on, voltmeter 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 between 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 No. 5 (Light Green/Black wire) on Engine Control Module (ECM) and ground.
13. With A/C switch on, 10-14 volts should exist. With A/C switch off, less than 1.5 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.

COMPRESSOR LOCK SENSOR

Unplug compressor lock sensor connector, located at compressor. Measure resistance between sensor terminals No. 1 and 2 at temperature specified. (Scheme 20) Replace sensor if resistance is not 65-125 ohms at 68°F (20°C).

Scheme 20

ENGINE COOLANT TEMPERATURE SENSOR

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

ENGINE COOLANT TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

EVAPORATOR TEMPERATURE SENSOR

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

EVAPORATOR TEMPERATURE SENSOR RESISTANCE SPECIFICATIONS

HEATER MAIN RELAY CIRCUIT

1. Turn ignition on. Inspect HEATER fuse, in fuse block, at driver's side kick 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 connected. Turn ignition off. Check for voltage between A/C control assembly connector terminal A14-10 (Blue/White wire) and ground. (Scheme 11) If battery voltage does not exist, go to next step. If battery voltage exists, repair short to voltage in Blue/White wire between connector and heater main relay.
3. Turn ignition on. Check for voltage between A/C control assembly connector terminal A14-10 (Blue/White wire) and 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 21) 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 A/C control assembly connector and battery.

Scheme 21

IGNITION POWER & GROUND CIRCUITS

1. Turn ignition on. Inspect HEATER fuse, in fuse block, at driver's side kick 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 connected. Turn ignition on. Using DVOM, backprobe between connector terminals A14-26 (Blue/Black wire) and A14-14 (White/Black wire). (Scheme 11) If battery voltage does not exist, go to next step. If battery voltage exists, circuit is okay.
3. Turn ignition off. Unplug A/C control assembly connector. Inspect Red/Blue wire between connector A14-26 terminal and HEATER fuse for continuity or short to ground. Repair wire as necessary. If wire is okay, go to next step.
4. Measure resistance between terminal A14-14 (White/Black wire) and ground. If resistance is less than one ohm, wire is okay. Repair open White/Black wire 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

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