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Headlight & Taillight System: Inspection

  1. FAIL-SAFE FUNCTION (Light Control ECU) 
    LIGHT CONTROL ECU FAIL-SAFE FUNCTION

    When input error is inspected. When input voltage is not within the range of operation voltage (9 to 16 V), lighting of the headlight stops. As soon as the voltage comes within the range, it lights up again.
    However if the input voltage becomes low after lighting up, sufficient voltage is maintained until light of bulb completely goes off.
    When output error is inspected (Open or short).
    When light flushing is inspected.    		 When an error occurs in the output voltage (open or short) or flushing symptom occurs on the bulb, lighting of the headlight stops, the condition is maintained until power is turned ON again (headlight dimmer switch OFF --> ON).
    In this case, it can not be judged whether lighting malfunction is caused by an output error or other reasons (fuse blown out, etc.).
    Check that there is no error in fuse and wiring (including power source) and replace the bulb in the first place, when the error still appears, replace the light control ECU.
  2. INSPECT LIGHT CONTROL SWITCH CONTINUITY 
    Fig 1: Inspecting Light Control Switch
    G03598694Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    LIGHT CONTROL SWITCH CONTINUITY

    Switch position Tester connection Specified condition
    OFF - No continuity
    TAIL 15 - 16 Continuity
    HEAD 14 - 15 - 16 Continuity
    AUTO 13 - 16 Continuity

    If continuity is not as specified, replace the switch.

  3. INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY 
    HEADLIGHT DIMMER SWITCH CONTINUITY

    Switch position Tester connection Specified condition
    Low beam 17 - 18 Continuity
    High beam 8 - 17 Continuity
    Flash 8 - 9 - 17 Continuity

    If continuity is not as specified, replace the switch.

  4. Connector disconnected: INSPECT LIGHT CONTROL SWITCH CIRCUIT (See  LIGHT CONTROL SWITCH CIRCUIT  ) 

    Disconnect the connector from the switch and inspect the connector on the wire harness side, as shown in Fig 2.

    Fig 2: Identifying Terminal Of Light Control Switch Connector
    G03598695Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    LIGHT CONTROL SWITCH CONNECTOR SPECIFIED CONDITION

    Tester connection Condition Specified condition
    16 - Ground Constant Continuity

    If circuit is not as specified, inspect the wire harness.

  5. Connector disconnected: INSPECT HEADLIGHT DIMMER SWITCH CIRCUIT (See  HEADLIGHT RELAY CIRCUIT  ) 

    Disconnect the connector from the switch and inspect the connector on the wire harness side, as shown in Fig 3.

    Fig 3: Identifying Terminals Of Headlight Dimmer Switch Connector
    G03598696Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    HEADLIGHT DIMMER SWITCH CONNECTOR SPECIFIED CONDITION

    Tester connection Condition Specified condition
    17 - Ground Constant Continuity
    9 - Ground Light control switch HEAD Battery positive voltage

    If circuit is not as specified, inspect the wire harness.

  6. Connector connected: INSPECT LIGHT CONTROL SWITCH CIRCUIT 

    Connect the wire harness side connector to the light control and dimmer switch and inspect the connector from the back side, as shown in Fig 4.

    Fig 4: Inspecting Light Control Switch Circuit Connector
    G03598697Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    LIGHT CONTROL SWITCH CIRCUIT CONNECTOR SPECIFIED CONDITION

    Tester connection Condition Specified condition
    13 - Ground Light control switch OFF, TAIL or HEAD No voltage
    13 - Ground Light control switch AUTO Battery positive voltage
    14 - Ground Light control switch OFF or TAIL No voltage
    14 - Ground Light control switch HEAD Battery positive voltage
    15 - Ground Light control switch OFF No voltage
    15 - Ground Light control switch TAIL or HEAD Battery positive voltage

    If circuit is not as specified, inspect the wire harness.

  7. Connector connected: INSPECT HEADLIGHT DIMMER SWITCH CIRCUIT 

    Connect the wire harness side connector to the light control and dimmer switch and inspect the connector from the back side, as shown.

    Fig 5: Inspecting Headlight Dimmer Switch Circuit Connector
    G03598698Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    HEADLIGHT DIMMER SWITCH CIRCUIT CONNECTOR SPECIFIED CONDITION

    Tester connection. Condition Specified condition
    8 - Ground Headlight dimmer switch FLASH No voltage
    Light control switch HEAD and dimmer switch HIGH
    8 - Ground Light control switch HEAD and Battery positive voltage
    dimmer switch LOW
    18 - Ground Light control switch HEAD and No voltage
    dimmer switch LOW and fog light switch ON
    18 - Ground Light control switch HEAD and Battery positive voltage
    dimmer switch HIGH or FLASH and fog light switch ON

    If circuit is not as specified, inspect the wire harness.

  8. INSPECT DAYTIME RUNNING LIGHT NO. 3 AND NO. 4 RELAY CONTINUITY 
    Fig 6: Inspecting Daytime Running Light No. 3 And No. 4 Relay Continuity
    G03598699Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    DAYTIME RUNNING LIGHT NO. 3 AND NO. 4 RELAY CONTINUITY

    Tester connection Condition Specified condition
    A1 - B3 Constant Continuity
    A3 - A5 Constant Continuity
    B3 - B4 Constant Continuity
    A2 - A5 Apply battery positive voltage between terminals A1 and B3. Continuity
    B1 - B2 Apply battery positive voltage between terminals B3 and B4. Continuity

    If continuity is not as specified, replace the relay.

  9. INSPECT HEADLIGHT CONTROL RELAY CONTINUITY 
    HEADLIGHT CONTROL RELAY CONTINUITY

    Condition Tester connection Specified condition
    Constant 1 - 2 Continuity
    Apply B+ between terminals 1 and 2. 3 - 4 Continuity

    If continuity is not as specified, replace the relay.

  10. INSPECT HEADLIGHT CONTROL RELAY CIRCUIT 

    (See  HEADLIGHT RELAY CIRCUIT  and  INSPECTION  ) 

    Fig 7: Inspecting Headlight Control Relay Continuity
    G03598700Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  11. INSPECT HEADLIGHT DIMMER (DAYTIME RUNNING LIGHT NO. 2) RELAY CONTINUITY 
    HEADLIGHT DIMMER (DAYTIME RUNNING LIGHT NO. 2) RELAY CONTINUITY

    Condition Tester connection Specified condition
    Constant 1 - 4
    2 - 4    		 Continuity
    Apply B+ between terminals 2 and 4. 1 - 3 - 4 Continuity

    If continuity is not as specified, replace the relay.

    Fig 8: Inspecting Headlight Dimmer (Daytime Running Light No. 2) Relay Continuity
    G03598701Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  12. INSPECT HEADLIGHT DIMMER (DAYTIME RUNNING LIGHT NO. 2) RELAY CIRCUIT (See page  INSPECTION  ) 
  13. INSPECT TAILLIGHT CONTROL RELAY CONTINUITY 
    TAILLIGHT CONTROL RELAY CONTINUITY

    Condition Tester connection Specified condition
    Constant 1 - 2 Continuity
    Apply B+ between terminals 1 and 2. 3 - 5 Continuity

    If continuity is not as specified, replace the relay.

  14. INSPECT TAILLIGHT CONTROL RELAY CIRCUIT (See  TAILLIGHT RELAY CIRCUIT  and  INSPECTION  ) 
    Fig 9: Inspecting Taillight Control Relay Continuity
    G03598702Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  15. INSPECT DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT 

    Disconnect the connector from the relay and inspect the connector on the wire harness side.

    Fig 10: Identifying Daytime Running Light Main Relay Circuit Connector Terminals
    G03598703Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    DAYTIME RUNNING LIGHT MAIN RELAY CIRCUIT CONNECTOR SPECIFIED CONDITION

    Tester connection Condition Specified condition
    2 - Ground Light control switch OFF or TAIL No continuity
    2 - Ground Light control switch HEAD Continuity
    4 - Ground Parking brake switch OFF No continuity
    (Parking brake pedal released)
    4 - Ground Parking brake switch ON Continuity
    (Parking brake pedal depressed)
    6 - Ground Constant Continuity
    8 - Ground Headlight dimmer switch LOW beam No continuity
    8 - Ground Headlight dimmer switch HIGH beam or FLASH Continuity
    1 - Ground Ignition switch LOCK or ACC No voltage
    1 - Ground Ignition switch ON or START Battery positive voltage
    5 - Ground Engine Stop No voltage
    5 - Ground Engine Running Battery positive voltage
    7 - Ground Constant Battery positive voltage
    9 - Ground Constant Battery positive voltage

    If circuit is specified, try replacing the relay with a new one.

    If circuit is not as specified, inspect the circuits connected to other parts.

  16. AUTO ON: INSPECT AUTOMATIC LIGHT CONTROL 
    1. Turn the ignition switch ON.
    2. Turn the light control switch to AUTO.
    3. Gradually cover the top Of the sensor.
    4. Check the accessory lights and the headlights should turn ON.
      5. Fig 11: Inspecting Automatic Light Control (AUTO ON)
      G03598704Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  17. AUTO OFF: INSPECT AUTOMATIC LIGHT CONTROL 
    1. Gradually expose the sensor.
    2. Check the headlights and the accessory lights should turn OFF.
      3. Fig 12: Inspecting Automatic Light Control (AUTO OFF)
      G03598705Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  18. INSPECT LIGHT-OFF CONDITION 
    1. Turn the ignition switch ON.
    2. Lights auto ON:

      Gradually cover the top of the sensor.

    3. Check that the lights go off under the following conditions.
      1. Light control switch is OFF.
      2. The area surrounding the sensor gets bright.
      3. The driver's door is opened with the ignition switch OFF.
  19. INSPECT LIGHTS-ON CONDITION 
    1. Open the driver's door while the ignition switch is OFF.
    2. Turn the light control switch to AUTO leaving the door open and cover the top of the sensor, and verify that the lights go on when the ignition switch is turned ON.
  20. Connector disconnected: INSPECT AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT 

    Disconnect the connector from the sensor and inspect the connector on the wire harness side, as shown in AUTOMATIC LIGHT CONTROL SENSOR CONNECTOR SPECIFIED CONDITION  .

    Fig 13: Identifying Terminals Of Automatic Light Control Sensor Connector
    G03598706Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    AUTOMATIC LIGHT CONTROL SENSOR CONNECTOR SPECIFIED CONDITION

    Tester connection Condition Specified condition
    3 - Ground Constant Continuity
    1 - Ground Ignition switch LOCK or ACC No voltage
    1 - Ground Ignition switch ON Battery positive voltage
    4 - Ground Ignition switch LOCK or ACC No voltage
    4 - Ground Ignition switch ON 5.2 - 9.0 V

    If circuit is as specified, perform the inspection on the following page.

    If the circuit is not as specified, inspect the circuit connected to other parts.

  21. Connector connected: INSPECT AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT 

    Connect the wire harness side connector to the sensor and inspect wire harness side connector from the back side, as shown.

    HINT:

    • Ignition switch ON.
    • Light control switch AUTO.
    • Vehicle's surroundings are bright.
      Fig 14: Inspecting Automatic Light Control Sensor Circuit
      G03598707Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT SPECIFIED CONDITION

      Tester connection Condition Specified condition
      3 - Ground Constant Continuity
      1 - Ground Ignition switch LOCK or ACC No voltage
      1 - Ground Ignition switch ON 9.5 V or more
      Vehicle is under the direct sun light. (Sensor is not covered) Taillight and Headlight are ON.

      If circuit is as specified, try replacing the sensor with a new one. If the circuit is not as specified, inspect the circuit connected to other parts.

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