Lexus SC300 / Lexus SC400. Service manual — part 983

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HOW TO USE THIS MANUAL

WITH THE IGNITION SW TURNED ON, THE CURRENT FLOWS TO TERMINAL 3 OF THE POWER WINDOW MASTER SW, TERMINAL 2 OF THE POWER WINDOW CONTROL RELAY
AND TERMINAL 8 OF THE POWER WINDOW SW THROUGH THE DOOR FUSE.

1.

DRIVER’S WINDOW “MANUAL UP” OPERATION BY MASTER SW

HOLDING MANUAL SW (DRIVER’S) ON “UP” POSITION LOCATED IN POWER WINDOW MASTER SW, THE CURRENT FLOWS TO TERMINAL 5 OF THE POWER WINDOW
CONTROL RELAY THROUGH TERMINAL 3 OF THE MASTER SW

TERMINAL 2 TO OPERATE A POWER WINDOW CONTROL RELAY. THUS THE CURRENT INSIDE THE RELAY

FLOWS FROM TERMINAL 2 OF THE RELAY

TERMINAL 1

TERMINAL 2 OF THE POWER WINDOW MOTOR

TERMINAL 1

TERMINAL 4 OF THE RELAY

TERMINAL

3

TO GROUND. THE MOTOR TURNS TO ASCENT THE WINDOW. RELEASING THIS SW, THE ROTATION OF MOTOR IS STOPPED AND THE WINDOWS CAN STOP AT WILL

POINT.

(FOR THE “MANUAL DOWN” OPERATION, CURRENT FLOWS IN THE REVERSE DIRECTION BECAUSE THE TERMINALS WHERE IT FLOWS ARE CHANGED).

2.

DRIVER’S WINDOW “AUTO DOWN” OPERATION BY MASTER SW

ONCE THE “AUTO DOWN” BUTTON OF THE MASTER SW IS PUSHED, THE CURRENT FLOWS TERMINAL 9 OF THE POWER WINDOW CONTROL RELAY THROUGH TERMINAL
3 OF THE MASTER SW

TERMINALS 8 AND 9 TO OPERATE THE RELAY. THUS THE CURRENT INSIDE THE POWER WINDOW CONTROL RELAY FLOWS FROM TERMINAL

2 OF THE RELAY

TERMINAL 4

TERMINAL 1 OF THE POWER WINDOW MOTOR

TERMINAL 2

TERMINAL 1 OF THE RELAY

TERMINAL 3

TO GROUND.

THE MOTOR CONTINUES THE ROTATION ENABLING TO DESCENT THE WINDOW.

THE WINDOW DESCENDS TO THE END POSITION. THE CURRENT WILL BE CUT OFF TO RELEASE THE AUTO DOWN FUNCTION BASED ON THE INCREASING CURRENT
BETWEEN TERMINAL 2 OF THE RELAY AND TERMINAL 1 IN RELAY.

3.

DRIVER’S WINDOW AUTO DOWN RELEASE OPERATION BY MASTER SW

HOLDING THE MANUAL SW (DRIVER’S) ON “UP” POSITION IN OPERATING AUTO DOWN. THE CURRENT FROM TERMINAL 3 OF THE MASTER SW PASSING TERMINAL 2
FLOWS TERMINAL 5 OF THE RELAY AND RELEASES THE AUTO DOWN FUNCTION IN THE POWER WINDOW CONTROL RELAY. RELEASING THE HAND FROM SW, WINDOW
STOPS AND CONTINUING ON TOUCHING SW, THE FUNCTION SWITCHES TO MANUAL UP OPERATION.

4.

PASSENGER’S WINDOW UP OPERATION (MASTER SW) AND WINDOW LOCK SW OPERATION

HOLDING PASSENGER’S WINDOW SW (MASTER SW) ON “UP”, THE CURRENT FLOWS FROM TERMINAL 3 OF THE MASTER SW PASSING TERMINAL 6 TO TERMINAL 3 OF
THE POWER WINDOW SW (PASSENGER’S)

TERMINAL 4

TERMINAL 2 OF THE MOTOR

TERMINAL 1

TERMINAL 9 OF THE POWER WINDOW SW

TERMINAL

7

TERMINAL 1 OF THE MASTER SW

TERMINAL 4 TO GROUND. THE MOTOR RUNS TO ASCENT THE WINDOW. RELEASING THIS SW, THE ROTATION OF MOTOR IS

STOPPED AND WINDOW CAN STOP AT WILL PLACE.

SWITCHING THE WINDOW LOCK SW IN “LOCK” POSITION, THE CIRCUIT IS OPENED AND STOPPED THE MOTOR ROTATION.

(FOR THE DOWN OPERATION, CURRENT FLOWS IN THE REVERSE DIRECTION BECAUSE THE TERMINALS WHERE IT FLOWS ARE CHANGED).

P 2 POWER WINDOW CONTROL RELAY

3–GROUND: ALWAYS CONTINUITY

2–GROUND: APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION

5–GROUND: APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION AND MASTER SW AT UP POSITION

8–GROUND: APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION AND MASTER SW AT AUTO DOWN POSITION

9–GROUND: APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION AND MASTER SW AT DOWN OR AUTO DOWN POSITION

P 4 POWER WINDOW MASTER SW

4–GROUND: ALWAYS CONTINUITY

3–GROUND: APPROX. 12 VOLTS WITH IGNITION SW AT ON POSITION

WINDOW LOCK SW

OPEN WITH WINDOW LOCK SW AT LOCK POSITION

: PARTS LOCATION

CODE

SEE PAGE

CODE

SEE PAGE

CODE

SEE PAGE

P 2

21

P 4

21

P 6

21

P 3

21

P 5

21

21

: RELAY BLOCKS

CODE

SEE PAGE

RELAY BLOCK (RELAY BLOCK LOCATION)

1

16

R/B NO. 1 (INSTRUMENT PANEL LEFT SIDE)

: JUNCTION BLOCK AND WIRE HARNESS CONNECTOR

CODE

SEE PAGE

JUNCTION BLOCK AND WIRE HARNESS (CONNECTOR LOCATION)

3B

14

J/B NO. 3 AND COWL WIRE (INSTRUMENT PANEL LEFT SIDE)

: CONNECTOR JOINING WIRE HARNESS AND WIRE HARNESS

CODE

SEE PAGE

JOINING WIRE HARNESS AND WIRE HARNESS (CONNECTOR LOCATION)

ID1

26

FRONT DOOR RH WIRE AND COWL WIRE (RIGHT KICK PANEL)

IH1

26

FRONT DOOR LH WIRE AND COWL WIRE (LEFT KICK PANEL)

: GROUND POINTS

CODE

SEE PAGE

GROUND POINT LOCATION

IC

24

COWL LEFT

: SPLICE POINTS

CODE

SEE PAGE

WIRE HARNESS WITH SPLICE POINTS

I 5

24

COWL WIRE

SYSTEM OUTLINE

SERVICE HINTS

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: Explains the system outline.

: Indicates values or explains the function for reference during troubleshooting.

: Indicates the reference page showing the position on the vehicle of the parts in the system circuit.

Example: Part “P4” (Power Window Master SW) is on page 21 of the manual.

* The letter in the code is from the first letter of the part, and the number indicates its order

in parts starting with that letter.

Part is 4th in order
Power Window Master SW

Example: P 4

: Indicates the reference page showing the position on the vehicle of Relay Block Connectors in the

system circuit.

Example: Connector “1” is described on page 16 of this manual and is installed on the left side of the

instrument panel.

: Indicates the reference page showing the position on the vehicle of J/B and Wire Harness in the system

circuit.

Example: Connector “3B” connects the Cowl Wire and J/B No. 3. It is described on page 14 of this

manual, and is installed on the instrument panel left side.

: Indicates the reference page describing the wiring harness and wiring harness connector (the female

wiring harness is shown first, followed by the male wiring harness).

Example: Connector “ID1”connects the front door RH wire (female) and cowl wire (male). It is described

on page 26 of this manual, and is installed on the right side kick panel.

: Indicates the reference page showing the position of the ground points on the vehicle.

Example: Ground point “IC” is described on page 24 of this manual and is installed on the cowl left side.

: Indicates the reference page showing the position of the splice points on the vehicle.

Example: Splice point “I 5” is on the Cowl Wire Harness and is described on page 24 of this manual.

* The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

POWER SOURCE (Current Flow Chart)

The chart below shows the route by which current flows from the battery to each electrical source (Fusible Link, Circuit
Breaker, Fuse, etc.) and other parts.
The next page and following pages show the parts to which each electrical source outputs current.

POWER SOURCE

8

HOW TO USE THIS MANUAL

The “Current Flow Chart” section, describes which parts each power source (fuses, fusible links, and circuit breakers)
transmits current to. In the Power Source circuit diagram, the conditions when battery power is supplied to each system are
explained. Since all System Circuit diagrams start from the power source, the power source system must be fully understood.

* The system shown here is an EXAMPLE ONLY. It is different to the actual circuit shown in the SYSTEM CIRCUITS SECTION.

GROUND POINT

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The ground points circuit diagram shows the connections from all major parts to the respective ground points. When
troubleshooting a faulty ground point, checking the system circuits which use a common ground may help you identify the
problem ground quickly. The relationship between ground points (

,

, and

shown below) can also be

checked this way.