Lexus SC300 / Lexus SC400. Service manual - part 211

ASSEMBLY OF COMBINATION SWITCH

INSTALL PARTS OF COMBINATION SWITCH IN RE-
VERSE SEQUENCE OF DISASSEMBLY

(MAIN POINT OF INSTALLATION)

1. 

INSTALL LIGHT CONTROL SWITCH
(a)  Slide the switch and install the switch body.
(b)  Set the lever in the HI position, and install the ball and

plate.

(c) After 

installing the light control switch to the switch body,

insure that the switch operation is smooth.

2. 

INSTALL TERMINALS TO CONNECTOR

•

Push in the terminal until it is securely locked in the
connector lug.

•

Install each switch terminal as shown in the figure.

–

BODY ELECTRICAL SYSTEM

Lighting System

BE–45

INSPECTION OF COMBINATION SWITCH

1. 

INSPECT LIGHT CONTROL SWITCH
(Continuity)
Inspect the switch continuity between terminals.

If continuity is not as specified, replace the switch.

2. 

INSPECT DIMMER SWITCH
(Continuity)
Inspect the switch continuity between terminals.

If continuity is not as specified, replace the switch.

3. 

INSPECT TURN SIGNAL SWITCH
(Continuity)
Inspect the switch continuity between terminals.

If continuity is not as specified, replace the switch.

4. 

INSPECT CORNARING LIGHT SWITCH
(Continuity)
Inspect the switch continuity between terminals.

If continuity is not as specified, replace the switch.

BE–46

–

BODY ELECTRICAL SYSTEM

Lighting System

5. USA

INSPECT COMBINATION SWITCH CIRCUIT
(a)  Pull the spool body to forward and separate spool body

from steering column.

(b) Connect the wire  harness side connector to the

combination switch and inspect wire harness side
connector from the back side as shown.

(Light Control Switch Circuit)

Check for

Tester connection

Condition

Specified value

Continuity

B4–Ground

Constant

Continuity

(Dimmer Switch Circuit)

Check for

Tester connection

Condition

Specified value

*

1

B7 Ground

Light Control Switch Position

OFF or TAIL

No voltage

*

1

B7–Ground

Light Control Switch Position

HEAD

Battery voltage

Voltage

Low beam

No voltage

*

1

B9–Ground

Dimmer Switch Position

Flash or High
beam

Battery voltage

Continuity

B18–Ground

Constant

Continuity

*1: USA

(Turn Signal Switch Circuit)

Check for

Tester connection

Condition

Specified value

Voltage

A3–Ground

Hazard Warning Switch ON

Battery voltage
 

↔

0 V

Ignition Switch ON and turn
signal switch position

Right

Battery voltage
 

↔

0 V

A4–Ground

Hazard Warning Switch ON

Battery voltage
 

↔

0 V

Ignition Switch ON and turn
signal switch position

Left

Battery voltage
 

↔

0 V

Continuity

A12–Ground

Constant

Continuity

(Cornaring Light Control Switch Circuit)

Check for

Tester connection

Condition

Specified value

Voltage

A8–Ground

Light control switch HEAD and

LO

Battery voltage

g

g

dimmer switch position

HI or FLASH

No voltage

Continuity

A10–Ground

Constant

*

2

 Continuity

y

A11–Ground

Constant

*

2

Continuity

*

2

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

If the circuit is not as specified, refer to 

BE–34

 wiring diagram

and inspect the circuits connected to other parts.

–

BODY ELECTRICAL SYSTEM

Lighting System

BE–47

(Headlight Control Relay)
INSPECTION OF HEADLIGHT CONTROL
RELAY

INSPECT HEADLIGHT CONTROL RELAY

(Continuity)
Inspect relay continuity between terminals.

If continuity is not as specified, replace the relay.
(Relay Circuit)
(See page

BE–21

)

(Headlight Dimmer Relay)
INSPECTION OF HEADLIGHT DIMMER
RELAY

INSPECT HEADLIGHT DIMMER RELAY

(Continuity)
Inspect relay continuity between terminals.

If continuity is not as specified, replace the relay.

BE–48

–

BODY ELECTRICAL SYSTEM

Lighting System