Lexus SC300 / Lexus SC400. Manual - part 216

INSPECTION OF STOP LIGHT SWITCH

INSPECT STOP LIGHT SWITCH

(Continuity)
Inspect the switch continuity between terminals.

If continuity is not as specified, replace the switch.
(Switch Circuit)
Disconnect the connector from the switch and inspect the
connector on the wire harness side as shown.

Check for

Tester connection

Condition

Specified value

Voltage

2–Ground

Constant

Battery voltage

If circuit is not as specified, inspect power source or wire har-
ness.

(Light Failure Sensor)

REMOVAL AND INSTALLATION OF
LIGHT FAILURE SENSOR

1. 

REMOVE LIGHT FAILURE SENSOR
(a)  Remove luggage front trim cover.
(b)  Remove a clip and disconnect connector.
(c)  Remove light failure sensor.

2. 

INSTALL LIGHT FAILURE SENSOR
For installation, follow the removal procedure in reverse.

BE–62

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BODY ELECTRICAL SYSTEM

Lighting System

INSPECTION OF LIGHT FAILURE
SENSOR

INSPECT LIGHT FAILURE SENSOR

(Relay Circuit)
Disconnect the connector from the sensor and inspect the
connector on the wire harness side as shown.

Check for

Tester connection

Condition

Specified value

Continuity

1–Ground

Constant

*Continuity

2–Ground

Constant

*Continuity

3–Ground

Constant

*Continuity

9–Ground

Constant

*Continuity

11–Ground

Constant

Continuity

Voltage

3–Ground

Tail or Head

OFF

No voltage

ON

Battery voltage

4–Ground

Ignition switch

LOCK or ACC

No voltage

ON

Battery voltage

7–Ground

Stop light switch

OFF

No voltage

ON

Battery voltage

Voltage

8–Ground

Ignition switch

LOCK or ACC

No voltage

ON

Battery voltage

*: There is resistance because this circuit is grounded through the bulb

*: There is resistance because this circuit is grounded through the bulb.

If circuit is as specified, replace the sensor. If the circuit is not
as specified, refer to 

BE–60

  wiring diagram and inspect the

circuits connected to other parts.

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BODY ELECTRICAL SYSTEM

Lighting System

BE–63

Troubleshooting
Stop Light System

You will find the cause of trouble more easily using the table shown.  In this table, the numbers indicate the order
priority of the causes in trouble.  Check each part in the order shown.  If necessary, replace the parts.

See page

Part

name

Trouble

Stop light does not light up.

Stop light always lights up.

Only one light always lights up.

Only one light does not light up.

BE–4

, 20

BE–61

BE–62

BE–6

ST

OP Fuse

Stop Light Switch

Light Failure Sensor

Wire Harness

Bulb

BE–64

–

BODY ELECTRICAL SYSTEM

Lighting System

(TURN SIGNAL AND HAZARD WARNING
LIGHT SYSTEM)
Description – TURN SIGNAL AND
HAZARD WARNING LIGHT SYSTEM

The component parts of this system and their function are as shown in the following table.

Parts Name

Function

Turn Signal Switch

Switches current from the turn signal flasher to the left side or right side.

Hazard Warning
Switch

Modifies the circuit to the flasher relay and turn signal switch in accordance with the
respective switch positions.

Turn Signal Flasher

Receives current from the hazard warning switch and flashes the turn signal lights by
switching the current to the lights ON and OFF.

PARTS LOCATION – TURN SIGNAL

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BODY ELECTRICAL SYSTEM

Lighting System

BE–65