Section 968 (Headlight & Taillight System): Inspection

WARNING: This page is about a different car, the 2003 Lexus LS 430. However, it is still accessible from the selected car via links, so may be relevant.

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.

Fig 1: Inspecting Headlight Control Relay Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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 - 4	Continuity

If continuity is not as specified, replace the relay.

Fig 2: Inspecting Taillight Control Relay Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT HEADLIGHT DIMMER RELAY CONTINUITY

HEADLIGHT DIMMER RELAY CONTINUITY

Condition	Tester connection	Specified condition
Constant	1 - 2 3 - 4	Continuity
Apply B+ between terminals 1 and 2.	3 - 5	Continuity

If continuity is not as specified, replace the relay.

Fig 3: Inspecting Headlight Dimmer Relay Continuity

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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. Verify that the lights should turn ON the accessory lights and the headlights.
  
  Fig 4: Inspecting Automatic Light Control - Auto ON
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
AUTO OFF: INSPECT AUTOMATIC LIGHT CONTROL
1. Gradually expose the sensor.
2. Verify that the lights should turn OFF the headlights and the accessory lights.
  
  Fig 5: Inspecting Automatic Light Control - Auto OFF
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT LIGHT-OFF CONDITION
1. Turn the ignition switch ON.
2. Lights auto ON:
  Gradually cover the top of the sensor.
3. Verify that the lights will go out when light control switch position OFF or the area surrounding the sensor gets bright or open the driver's door while the ignition switch is OFF.
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.

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 the chart.

Fig 6: Identifying Automatic Light Control Sensor Connector Terminals (Wire Harness Side)

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

CONNECTOR SPECIFIED CONDITION

Tester connection	Condition	Specified condition
5 - Ground	Constant	Continuity
6 - Ground	Close the driver's door again while the ignition switch OFF	No voltage
6 - Ground	Ignition switch position ON	5.2 - 9.0 V
3 - Ground	Close the driver's door again while the ignition switch OFF	No voltage
3 - Ground	Ignition switch position ON	Battery positive voltage

If circuit is as specified, perform the inspection in the following step.

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

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 7: Identifying Automatic Light Control Sensor Connector Terminals (From Back Side)

CONNECTOR SPECIFIED CONDITION

Tester connection	Condition	Specified condition
6 - Ground (CLTS - Body ground)	Constant	Pulse generation
5 - Ground (CLTB - Body ground)	Ignition switch position ON	10 - 14 V

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