Manual Air Conditioning
LAN SYSTEM CIRCUIT
Description
SYMPTOM: Mode door motor, intake door motor and/or air mix door motor does not operate normally.
Diagnosis Procedure
Regarding Wiring Diagram information, Coupe or Sedan.
DIAGNOSIS PROCEDURE FOR LAN CIRCUIT
1. CHECK POWER SUPPLY FOR DOOR MOTORS
1.Press ignition switch ON.
2.Check voltage between front air control connector M37 terminal 13 and ground.
Is the inspection result normal?
YES- GO TO 2
NO- GO TO 3
2. CHECK SIGNAL FOR DOOR MOTORS
Check voltage between front air control connector M37 terminal 3 and ground.
Is the inspection result normal?
YES- GO TO 11
NO- GO TO 6
3. CHECK MODE DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 13 and ground, disconnect the mode door motor.
Is the inspection result normal?
YES- Replace mode door motor. Mode Door Motor.
NO- GO TO 4
4. CHECK INTAKE DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 13 and ground, disconnect the intake door motor.
Is the inspection result normal?
YES- Replace intake door motor. Intake Door Motor.
NO- GO TO 5
5. CHECK AIR MIX DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 13 and ground, disconnect the air mix door motor.
Is the inspection result normal?
YES- Replace air mix door motor. Service and Repair.
NO- GO TO 9
6. CHECK MODE DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 3 and ground, disconnect the mode door motor.
Is the inspection result normal?
YES- Replace mode door motor. Mode Door Motor.
NO- GO TO 7
7. CHECK INTAKE DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 3 and ground, disconnect the intake door motor.
Is the inspection result normal?
YES- Replace intake door motor. Intake Door Motor.
NO- GO TO 8
8. CHECK AIR MIX DOOR MOTOR FOR SHORT TO GROUND
While checking for voltage between front air control connector M37 terminal 3 and ground, disconnect the air mix door motor.
Is the inspection result normal?
YES- Replace air mix door motor. Service and Repair.
NO- GO TO 10
9. CHECK DOOR MOTOR POWER SUPPLY FOR SHORT TO GROUND
1.Disconnect front air controller connector M37.
2.Check for continuity between front air control connector M37 terminal 13 and ground.
Is the inspection result normal?
YES- Replace front air control. Service and Repair.
NO- Replace harness or connector.
10. CHECK A/C LAN SIGNAL FOR SHORT TO GROUND
1.Disconnect front air controller connector M37.
2.Check for continuity between front air control connector M37 terminal 3 and ground.
Is the inspection result normal?
YES- Replace front air control. Service and Repair.
NO- Replace harness or connector.
11. CHECK POWER SUPPLY FOR MOTORS
1.Press ignition switch OFF.
2.Disconnect mode door motor connector M127, intake door motor M126, and air mix door motor M130.
3.Press ignition switch ON.
4.Check voltage between mode door motor connector M127 terminal 3 and ground, between air mix door motor connector M130 terminal 3 and ground, and between intake door motor connector M126 terminal 3 and ground.
Is the inspection result normal?
YES- GO TO 12
NO- Replace harness or connector.
12. CHECK SIGNAL FOR MOTORS
Check voltage between mode door motor connector M127 terminal 1 and ground, between air mix door motor
M130 terminal 1 and ground, and between intake door motor connector M126 terminal 1 and ground.
Is the inspection result normal?
YES- GO TO 13
NO- Replace harness or connector.
13. CHECK MOTOR GROUND CIRCUIT
1.Press ignition switch OFF.
2.Check continuity between mode door motor connector M127 terminal 2 and ground, between air mix door motor connector M130 terminal 2 and ground, and between intake door motor connector M126 terminal 2 and ground.
Is the inspection result normal?
YES- GO TO 14
NO- Replace harness or connector.
14. CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - DISCHARGE AIR
1.Reconnect the front air control, mode door motor, air mix door motor, and intake door motor.
2.Press ignition switch ON.
3.Turn blower motor to maximum speed.
4.Press each of the four mode position switches and then press the (DEF) switch. Each position indicator should illuminate.
5.Confirm that discharge air comes out according to the air distribution table. System Description.
NOTE:
Confirm the intake door position is at (FRESH) when (DEF) or (D/F) is selected.
Is the inspection result normal?
YES- GO TO 15
NO- Replace mode door motor. Mode Door Motor.
15. CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - TEMPERATURE CHANGE
1.Start engine. Allow engine to reach operating temperature.
2.Press the A/C button to engage the A/C compressor. The A/C on indicator should illuminate.
NOTE:
Confirm that the A/C compressor clutch is engaged (visual inspection).
3.Press (VENT) mode position switch.
4.Turn the temperature control dial clockwise until 32�C (90�F) is displayed.
5.Check for hot air at discharge air outlets.
6.Turn the temperature control dial counterclockwise until 18�C (60�F) is displayed.
7.Check for cold air at discharge air outlets. is the inspection result normal?
YES- GO TO 16
NO- Replace air mix door motor. Service and Repair.
16. CONFIRM SYMPTOM BY PERFORMING OPERATION CHECK - REC ()
1.Press REC () switch. The REC () indicator should illuminate.
2.Press REC () switch again. The REC () indicator should go out.
3.Listen for intake door position change (you should hear the sound change slightly).
Is the inspection result normal?
YES- Intermittent incident. Intermittent Incident.
NO- Replace intake door motor. Intake Door Motor.