Lexus SC300 / Lexus SC400. Manual - part 141

INSPECTION OF MIRROR DEFOGGER

INSPECT MIRROR DEFOGGER

(a) Connect 

the positive (+) lead from the battery to terminal

7 and the negative (–) lead to terminal 8.

(b)  Check that the mirror becomes warm.
HINT: It will take a short time for the mirror to become warm.
If the mirror does not become warm, replace the mirror as-
sembly.

Troubleshooting

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

See page

BE–4

,20

BE–4

,20

BE–4

,22

BE–172

BE–173

    –

–

BE–173

    –

–

BE–174

Trouble

Parts

name

HEA

TER Fuse

MIR–HTR Fuse

DEFOG Fuse

Defogger Switch

Defogger Relay

Wire Harness

Defogger Wires

CKE Coil

Mirror Defogger

All defogger systems do not operate.

1

1

2

3

4

Rear window defogger does not operate.

3

1

2

Mirror Defogger does not operate.

1

3

2

–

BODY ELECTRICAL SYSTEM

Defogger System

BE–175

SLIDING ROOF SYSTEM

Description

Standby Operation

Current flows from the DOME fuse to terminal A1 of the sliding roof control relay (hereafter called
relay).

When the ignition switch is ON, the current flows from the power window relay to terminal A3 of the
relay.

Operation

Roof Position

Function

Fully

Open

Fully

Closed

Momentary

Stop

Limit

Switch

No. 1

Limit

Switch

No. 2

Sliding
Roof
Control
Switch

Down

Up

Sliding

Period

Idling Period

CLOSE

DOWN

OPEN

UP

ON

ON

OFF

OFF

Tilting

Period

2. OPEN 

operation

When the switch on the ”OPEN” side of the control switch is pushed, continuity is produced between termi-
nal A8 of the relay and body ground. Then the relay operates, the current flows through terminal A3 of the
relay 

 terminal B3 

 terminal 1 of the sliding roof motor 

 terminal 3 

 terminal B1 of the relay 

 terminal

A5 

 the body ground, and the motor starts to run in order to open the sliding roof.

3. CLOSE 

operation

When the switch on the ”CLOSE” side of the control switch is pushed, continuity is produced between termi-
nal A7 of the relay and body ground. Then the relay operates, the current flows through terminal A3 of the
relay 

 terminal B1 

 terminal 3 of the sliding roof motor 

 terminal 1 

 terminal B3 of the relay 

 terminal

A5 

 the body ground, and the motor starts to run in order to close the sliding roof.

Momentary Stop

When the sliding roof reaches about 200 mm (7.87 in.) short of the fully closed position, the limit switch
is turned from ON to OFF, so there is not continuity between terminal B1 of the relay and body ground No.
1. As a result, the sliding roof stops at that position.

4. 

TILT UP operation
When the switch on the ”UP” side of the control switch is pushed, continuity is produced between terminal
A6 of the relay and body ground. Then the relay operates, the current flows through terminal A3 of the relay

 terminal B1 

 terminal 3 of the sliding roof motor 

 terminal 1 

 terminal B3 of the relay 

 terminal

A5 

 the body ground, and the motor starts to run in order to tilt up the sliding roof.

5. 

TILT DOWN operation
When the switch on the ”DOWN” side of the control switch is pushed, continuity is produced between termi-
nal A2 of the relay and body ground. Then the relay operates, the current flows through terminal A3 of the
relay 

 terminal B3 

 terminal 1 of the sliding roof motor 

 terminal 3 

 terminal B1 of the relay 

 terminal

A5 

 the body ground, and the motor starts to run in order to tilt down the sliding roof.

BE–176

–

BODY ELECTRICAL SYSTEM

Sliding Roof System

6. 

TILT UP REMINDER SYSTEM
If the ignition switch is turned from ON to OFF or ACC and the sliding roof remains tilted up, after 60 seconds
have elapsed or either the driver or passenger door is opened, a buzzer will sound for approx. 8 seconds
as a reminder that the sliding roof is tilted up.

Parts Location

–

BODY ELECTRICAL SYSTEM

Sliding Roof System

BE–177

Wiring and Connector Diagrams

BE–178

–

BODY ELECTRICAL SYSTEM

Sliding Roof System