Lexus SC300 / Lexus SC400. Service manual — part 1022

185

CURRENT ALWAYS FLOWS TO TERMINAL 1 OF THE INTEGRATION RELAY THROUGH DOME FUSE.

1. SEAT BELT WARNING SYSTEM

WHEN THE IGNITION SW IS TURNED ON, CURRENT FLOWS FROM THE GAUGE FUSE TO TERMINAL 7 OF THE INTEGRATION RELAY.
AT THE SAME TIME, CURRENT FLOWS TO TERMINAL 9 OF THE RELAY FROM THE GAUGE FUSE THROUGH THE SEAT BELT
WARNING LIGHT. THIS CURRENT ACTIVATES THE INTEGRATION RELAY AND, FOR APPROX. 4–8 SECONDS, CURRENT FLOWING
THROUGH THE WARNING LIGHT FLOWS FROM TERMINAL 9 OF THE RELAY

→

TERMINAL 10

→

GROUND, CAUSING THE WARNING

LIGHT TO LIGHT UP. AT THE SAME TIME AS THE WARNING LIGHT LIGHTS UP, A BUCKLE SW OFF SIGNAL IS INPUT TO TERMINAL 8
OF THE RELAY, THE CURRENT FLOWING TO TERMINAL 7 OF THE RELAY FLOWS FROM TERMINAL 10

→

GROUND AND THE SEAT

BELT WARNING BUZZER SOUNDS FOR APPROX. 4–8 SECONDS. HOWEVER, IF THE SEAT BELT IS PUT ON DURING THIS PERIOD
(WHILE THE BUZZER IS SOUNDING), SIGNAL INPUT TO TERMINAL 8 OF RELAY STOPS AND THE CURRENT FLOW FROM TERMINAL 7
OF THE RELAY

→

TERMINAL 10

→

GROUND IS CUT, CAUSING THE BUZZER TO STOP.

2. UNLOCK WARNING SYSTEM

WITH THE IGNITION KEY INSERTED IN THE KEY CYLINDER (UNLOCK SW ON), THE IGNITION SW STILL OFF AND DOOR OPEN (DOOR
COURTESY SW ON), WHEN A SIGNAL IS INPUT TO TERMINAL 6 OF THE RELAY, THE INTEGRATION RELAY OPERATES, CURRENT
FLOWS FROM TERMINAL 7 OF THE RELAY

→

TERMINAL 10

→

GROUND AND UNLOCK WARNING BUZZER SOUNDS.

B 4

BUCKLE SW LH

1–2 : CLOSED WITH DRIVER’S LAP BELT IN USE

D10

DOOR COURTESY SW LH

3–6 : CLOSED WITH LH DOOR OPEN

I15

UNLOCK WARNING SW [IGNITION SW]

10–9: CLOSED WITH IGNITION KEY IN CYLINDER

INTEGRATION RELAY

10–GROUND: ALWAYS CONTINUITY

6–GROUND: CONTINUITY WITH DRIVER’S DOOR OPEN
5–GROUND: CONTINUITY WITH IGNITION KEY IN CYLINDER
8–GROUND: CONTINUITY WITH DRIVER’S LAP BELT IN USA
9–GROUND: 0 VOLTS FOR 4–8 SECONDS WITH IGNITION SW ON AND APPROX. 12 VOLTS 4–8 SECONDS AFTER IGNITION SW ON
1–GROUND: ALWAYS APPROX. 12 VOLTS

: PARTS LOCATION

CODE

SEE PAGE

CODE

SEE PAGE

CODE

SEE PAGE

B 4

32

C14

B

28

I15

29

C12

A

28

D10

30

: RELAY BLOCKS

CODE

SEE PAGE

RELAY BLOCKS (RELAY BLOCK LOCATION)

2

19

ENGINE COMPARTMENT LEFT

: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR

CODE

SEE PAGE

JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)

1B

20

ENGINE ROOM MAIN WIRE

1C

20

FLOOR MAIN

1D

20

FRONT DOOR LH WIRE

1E

20

INSTRUMENT PANEL WIRE

1H

1I

20

COWL WIRE

1J

20

COWL WIRE

3A

22

INSTRUMENT PANEL WIRE

3D

22

INSTRUMENT PANEL WIRE

: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS

CODE

SEE PAGE

JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)

Ba1

42

FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)

Ba2

42

FLOOR WIRE AND FRONT SEAT LH WIRE (UNDER THE FRONT LH SEAT)

: GROUND POINTS

CODE

SEE PAGE

GROUND POINTS LOCATION

IF

36

LEFT KICK PANEL

BK

40

UNDER THE CENTER PILLAR LH

SYSTEM OUTLINE

SERVICE HINTS