Section 570 (Headlight & Taillight System): Inspection

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

INSPECT LIGHT CONTROL SWITCH CONTINUITY

LIGHT CONTROL SWITCH CONTINUITY SPECIFICATIONS

Switch Position	Tester Connection	Specified Condition
OFF	-	No Continuity
TAIL	14 - 16	Continuity
HEAD	13 - 14 - 16	Continuity
AUTO	12 - 16	Continuity

If continuity is not as specified, replace the switch.

INSPECT HEADLIGHT DIMMER SWITCH CONTINUITY

HEADLIGHT DIMMER SWITCH CONTINUITY SPECIFICATIONS

Switch Position	Tester Connection	Specified Condition
Flash	7 - 8 - 16	Continuity
Low Beam	16 - 17	Continuity
High Beam	7 - 16	Continuity

If continuity is not as specified, replace the switch.

Fig 1: Identifying Light Control Switch And Connector Terminal

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT HEADLIGHT CONTROL RELAY CONTINUITY

Fig 2: Headlight Control Relay Continuity Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If continuity is not as specified, replace the relay.

Fig 3: Inspecting Headlight Control Relay Continuity
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT TAILLIGHT CONTROL RELAY CONTINUITY

Fig 4: Taillight Control Relay Continuity Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If continuity is not as specified, replace the relay.

Fig 5: Inspecting Taillight Control Relay Continuity
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
INSPECT DRL NO. 4 RELAY CIRCUIT

Fig 6: DRL No. 4 Relay Circuit Continuity Specifications
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

If continuity is not as specified, replace the relay.

Fig 7: Inspecting DRL No. 4 Relay Circuit
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

INSPECT DIMMER RELAY CIRCUIT

DIMMER RELAY CIRCUIT CONTINUITY SPECIFICATIONS

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 8: Inspecting Dimmer Relay Circuit

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. Check that the accessory lights and the headlights should turn ON.
AUTO OFF: INSPECT AUTOMATIC LIGHT CONTROL
1. Gradually expose the sensor.
2. Check that the headlights and the accessory lights should turn OFF.
INSPECT LIGHTS-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. (1) Light control switch is OFF.
  2. (2) The area surrounding the sensor gets bright.
  3. (3) After the ignition switch is turned OFF and after 30 sec. from when open doors are all closed.
    
    Fig 10: Inspecting Automatic Light Control (Auto Off)
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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. Make sure that the lights go on when the ignition switch is turned ON.
ADJUST AUTOMATIC LIGHT CONTROL SENSOR
1. Adjustment of the light control is performed by turning the sensitivity knob on the sensor.
2. This will be determined by light condition the automatic control will take place.
  - If response is too quick, turn the knob counterclockwise.
  - If response is too slow, turn the knob clockwise.
    
    Fig 11: Adjusting Automatic Light Control Sensor
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
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 in the table.
NOTE:
- Ignition switch ON.
- Light control switch AUTO.
- Vehicle's surroundings are bright.
  
  Fig 12: View Of Automatic Light Control Sensor Connector (From Back Side)
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  Fig 13: Automatic Light Control Sensor Circuit Continuity Specifications
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  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.

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 table.

Fig 14: View Of Automatic Light Control Sensor Connector (Wire Harness Side)

AUTOMATIC LIGHT CONTROL SENSOR CIRCUIT CONTINUITY SPECIFICATIONS

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 section.

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

INSPECT DAYTIME RESISTOR CONTINUITY

DAYTIME RESISTOR CONTINUITY SPECIFICATIONS

Condition	Tester Connection	Specified Condition
Constant	1 - 2	Approx. 337 mΩ

If continuity is not as specified, replace the resistor.

Fig 15: Inspecting Daytime Resistor Continuity