Page 138 of 1111
BE0GU±05
I01361
Ignition Switch
Buckle Switch
Driver Side Junction Block
ECU±IG Fuse
Electric Tension Reducer Solenoid
BE±104
± BODY ELECTRICALELECTRIC TENSION REDUCER SYSTEM
2405 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
ELECTRIC TENSION REDUCER SYSTEM
LOCATION
Page 141 of 1111
BE0GS±10
I01362
Defogger WireIgnition SwitchDefogger Switch
Defogger Switch
Mirror Assembly
Mirror Defogger
LEXUS navigation
System
Passenger Side
Junction Block
DEF M±Fuse
MIR HTR Fuse
Mirror Defogger Relay
Mirror Assembly
Mirror Defogger
Passenger Cowl Side
Relay Block
Defogger Relay
± BODY ELECTRICALDEFOGGER SYSTEM
BE±107
2408 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
DEFOGGER SYSTEM
LOCATION
Page 146 of 1111

Only specific window does not operate. (Neither manual nor automatic operation is available.)1
Diagnosis check:
Check output diagnosis trouble codes 21 ± 26 when operating the
master switch and power window switch.
(Refer to ºMultiplex Communication Systemº)If the door lock of the applicable seat operates.
Wire harness faulty or
D FR DOOR fuse faulty.
No Yes
Disconnect the driver door control ECU connector.
Ye sNo
Voltage check:
With ignition switch ON if 10 to 14 V power is
supplied to PCT (3) of power window switch.Wire harness faulty.
(Between master switch W/L2 terminal
(10) and power window switch PCT
terminal (3)
Continuity check:
Master switch faulty.
Check continuity master switch and power window switch.No (Driver side)
No (Except driver side)Ye s
No Ye s
Wire harness check:
Master switch
Master switch Driver door control ECU
AUTO (7)
DDN (18)
DUP (6)AUTO (B6)
MDN (B4)
MUP (B5)
Power window switch
Power window switch Driver door control ECU
A (5)
D (4)
U (6)AUTO (A22)
MDN (A23)
MUP (A24)
Wire harness faulty.
Continuity check:
Check continuity between UP terminal (A2) and
GND terminal (C12), DN terminal (A11) and
GND terminal (C12) of driver door control ECU .
Ye s
When replacing with the normal driver door control ECU
removed from another seat, if it operates normally.
Driver door control ECU faulty.No Yes
Driver door control ECU faulty.
No
Power window motor check:
Disconnect the motor connector.
Connect the battery positive (+) lead to terminal
UP (2) and negative (±) lead to terminal DN
(1) of wire harness side motor connector, check that
the motor operates.
Check power window motor.Ye s
No
Wire harness faulty.
Ye s
Power window motor faulty.
No
BE±112
± BODY ELECTRICALPOWER WINDOW CONTROL SYSTEM
2413 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
FLOW CHART
Page 174 of 1111
BE0GQ±03
I01365
Luggage Compartment
Courtesy SwitchIgnition Switch
Door Lock Assembly
Door Lock Motor
Door Unlock Detection
Switch
Door Key Lock and
Unlock Switch
Door Lock Assembly
Door Lock Motor
Door Unlock Detection
Switch
Door Key Lock and Unlock SwitchLuggage Compartment
Opener Switch
Luggage Compartment
Key Lock and Unlock
Switch
Horn Theft Deterrent HornEngine Room No.1 Junction Block
HORN Fuse
Headlight Control Relay
Starter Relay
Engine Hood Courtesy Switch
Driver Side Junction Block
ST Fuse
Taillight Control RelayEngine Room No.2 Relay Block
Horn Relay
BE±140
± BODY ELECTRICALTHEFT DETERRENT SYSTEM
2441 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
THEFT DETERRENT SYSTEM
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.
Page 190 of 1111

BE±156
± BODY ELECTRICALWIRELESS DOOR LOCK CONTROL SYSTEM
2457 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Ye s
Wireless door control receiver power source check:
Check that there is 4.5 ± 5.5 V voltage at the
connector terminal 3 (RCO) of wireless door control
receiver under the vehicle initialized condition.
(1) Check that the control receiver voltage becomes
0 V during transmitting.
(2) When RCO is turned ON compulsoring with a
LEXUS hand±held tester, check that the wireless door
lock control receiver voltage becomes 0 V.
No
ECU±B1 and MPX±B, or P FR DOOR fuse
or wire harness faulty.
Ye s
+B power source check:
Check that there is constantly10 to 14 V voltage at the
connector terminal 1 (+B) of wireless door control
receiver.
No
Wire harness faulty.
Body ground open and contact error.
Ye s
Body ground check:
Check that continuity exists between the connector
terminal 7 (GND) of the wireless door control receiver
and body ground.
No
Wireless door control receiver faulty.Wire harness faulty (open circuit)
Between the receiver terminal 3 (CONT) and
body ECU terminal B5 (RCO).
Page 196 of 1111
I04026
Engine Room No.1 Junction Block
Fuses Relays
1. MAIN H±Fuse
2. FL ABS NO.1 H±Fuse
3. ALT H±Fuse
4. ABS NO.2 H±Fuse
5. H±LP CLN H±Fuse
6. RAD NO.1 Fuse
7. ALT±S Fuse
8. EFI Fuse
9. TURN HAZ Fuse
10. TEL Fuse
11. AM2 Fuse
13. HORN Fuse 12. ETCS Fuse
14. MPX±B Fuse
15. ECU±B1 Fuse
16. HTR FuseB. Starter Relay A. Headlight Control Relay
C. EFI Relay
17. FAN MAIN H±Fuse
18. CDS FAN H±Fuse
20. H±LP R LWR Fuse 19. RAD FAN H±Fuse
21. H±LP L LWR Fuse
22. H±LP R UPR Fuse
23. H±LP L UPR Fuse1
2 3 4 5 6 7 8 9 10 11 12 13
14 15
16 18 17 19
20 21 22 23 A
BC
± BODY ELECTRICALPOWER SOURCE
BE±17
2318 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 197 of 1111
I04028
Engine Room No.3 Relay Block
Relays
A. FAN NO.1 Relay
B. FAN NO.2 Relay
C. A/C COMP Relay
D. FAN NO.3 Relay
Engine Room No.2 Relay Block
Relays
A. Horn Relay
B. ABS SOL Relay
C. TRC MTR Relay
D. ABS MTR Relay
I04027
I04028
A
B
C
D
EE. Headlight Dimmer
(Daytime Running Light No.2) Relay
A
B
C
DFuses
1. H±LP R UPR Fuse
(w/ Daytime Running Light System)
2 H±LP L UPR Fuse
(w/ Daytime Running Light System) 12 BE±18
± BODY ELECTRICALPOWER SOURCE
2319 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
Page 198 of 1111
I04029
Fuses
Relays 1. AM1 H±Fuse
2. WASHER Fuse
3. FOG Fuse
4. TAIL Fuse
B. Taillight Control Relay A. Fog Light Relay
C. Body ECU No.2 Driver Side Instrument Panel Junction Block
5. SRS±ACC Fuse
6. GAUGE Fuse
7. FUEL OPN Fuse
8. D FR DOOR Fuse
9. PANEL Fuse
10. HTR Fuse
11. SRS±B Fuse
12. P/SEAT (D) Fuse
13. RAD NO.2 Fuse
14. WIP Fuse
15. OBD Fuse
16. STOP Fuse
17. CIG Fuse
18. ECU±IG Fuse
19. STARTER Fuse
20. IGN Fuse
21. D FR DOOR Fuse
2
21 34 5
678 9
10 11 12 13
14 15 16 17
18 19 20AB
C 1
± BODY ELECTRICALPOWER SOURCE
BE±19
2320 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)