fuse LEXUS GS400 2000 Service Owner's Manual

23 Power Amplifier NO POWER COMING IN
+ B wire harness faulty.
GND faulty.
Power amplifier or wire harness faulty.
Power amplifier or wire harness faulty.
GND faulty. Is tape player operating normally?
Check if RAD±No.2 fuse is OK?Ye s
NG
No OK No
No
No
No OK
OK
OK Ye s
Ye s
Ye s
Ye sNG
NG
NG Check if RAD±No.1 fuse is OK?
Radio assembly faulty.Replace fuse.
ACC wire harness faulty. Radio assembly faulty.
Replace fuse.
Check if GND (wire harness side) of power amplifier
grounded normally?Is power supplied to ACC terminal of power amplifier?
Is power supplied to +B terminal of power amplifier?
Is power supplied to ACC terminal of radio assembly?
Is power supplied to +B terminal of radio assembly?
Check if GND (wire harness side) of radio assembly
grounded normally?
± BODY ELECTRICALAUDIO SYSTEM
BE±211
2512 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

24 Power AmplifierPOWER COMIMG IN, BUT WOOFER (POWER) AMPLIFIER NOT
OPERATING
+ B wire harness faulty.
GND faulty.
Power amplifier faulty.
Speaker wire harness faulty. GND faulty. Is tape player operating normally?
Check if RAD±No.2 fuse is OK?Ye s
NG
No OK No
No
No
No OK
OK
OK Ye s
Ye s
Ye s
Ye sNG
NG
NG Check if RAD±No.1 fuse is OK?
Radio assembly faulty. Recheck system after repair.Replace fuse.
ACC wire harness faulty. Radio assembly faulty.
Replace fuse.
Is there continuity in speaker wire harness?
Temporarily install another speaker. Functions OK?
Hiss noise from speaker?Ye s
Ye s NoNo
No Ye sPower amplifier faulty.
Power amplifier faulty.
Recheck system after repair. Speaker faulty.
Is power supplied to ACC terminal of power amplifier?
Check if GND (wire harness side) of power amplifier
grounded normally? Is power supplied to +B terminal of power amplifier?
Is power supplied to ACC terminal of radio assembly?
Is power supplied to +B terminal of radio assembly?
Check if GND (wire harness side) of radio assembly
grounded normally? BE±212
± BODY ELECTRICALAUDIO SYSTEM
2513 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

BE04S±04
I05031
± BODY ELECTRICALPOWER SOURCE
BE±21
2322 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT ENGINE ROOM NO.1 JUNCTION BLOCK
CIRCUIT
(a) Remove the fuse from the junction block and inspect the
connector on junction block side.
Fuse Tester connectionConditionSpecified condition
MAIN 2 ± GroundConstantBattery positive voltage
ABS NO.1 4 ± GroundConstantBattery positive voltage
ALT 6 ± GroundConstantBattery positive voltage
ABS 8 ± GroundConstantBattery positive voltage
H±LP CLN 10 ± GroundConstantBattery positive voltage
RAD NO.1 12 ± GroundConstantBattery positive voltage
ALT±S 14 ± GroundConstantBattery positive voltage
EFI 16 ± GroundConstantBattery positive voltage
TURN HAZ 18 ± GroundConstantBattery positive voltage
TEL 20 ± GroundConstantBattery positive voltage
AM2 22 ± GroundConstantBattery positive voltage
ETCS 24 ± GroundConstantBattery positive voltage
HORN 26 ± GroundConstantBattery positive voltage
MPX±B 27 ± GroundConstantBattery positive voltage

I05032
± BODY ELECTRICALPOWER SOURCE
BE±23
2324 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. INSPECT ENGINE ROOM No.3 RELAY BLOCK CIR-
CUIT
Remove the relay from the relay block and inspect the connec-
tor on relay block side.
Fuse Tester connectionConditionSpecified condition
FAN NO.1 3 ± GroundIgnition switch ONBattery positive voltage
FAN NO.2 8 ± GroundIgnition switch ONBattery positive voltage
A/C COMP 13 ± GroundIgnition switch ONBattery positive voltage
FAN NO.3 17 ± GroundIgnition switch ONBattery positive voltage
DIMMER 20 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE±26
± BODY ELECTRICALPOWER SOURCE
2327 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(a) Remove the fuse from the junction block and inspect the
connector on junction block side.
Fuse Tester connectionConditionSpecified condition
AM1 1 ± GroundConstantBattery positive voltage
WASHER 3 ± GroundIgnition switch ONBattery positive voltage
FOG 5 ± GroundConstantBattery positive voltage
TAIL 7 ± GroundLight control switch TAIL or HEADBattery positive voltage
SRS±ACC 9 ± GroundIgnition switch ACC or ONBattery positive voltage
GAUGE 11 ± GroundIgnition switch ONBattery positive voltage
FUEL OPN 13 ± GroundConstantBattery positive voltage
D FR DOOR 15 ± GroundConstantBattery positive voltage
PANEL 17 ± GroundLight control switch TAIL or HEADBattery positive voltage
HTR 19 ± GroundIgnition switch ONBattery positive voltage
SRS±B 21 ± GroundConstantBattery positive voltage
P/SEAT (D) 23 ± GroundConstantBattery positive voltage
RAD NO.2 25 ± GroundIgnition switch ACC or ONBattery positive voltage
WIP 27 ± GroundIgnition switch ONBattery positive voltage
OBD 29 ± GroundConstantBattery positive voltage
STOP 31 ± GroundConstantBattery positive voltage
CIG 33 ± GroundIgnition switch ACC or ONBattery positive voltage
ECU±IG 35 ± GroundIgnition switch ONBattery positive voltage
ST 37 ± GroundIgnition switch ONBattery positive voltage
IGN 39 ± GroundIgnition switch ONBattery positive voltage
D RR DOOR 41 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
(b) Remove the relay from the junction block and inspect the
connector on junction block side.
Relay Tester connectionConditionSpecified condition
Fog light 43 ± GroundConstantBattery positive voltage
Fog light 44 ± GroundConstantContinuity
Fog light 46 ± GroundLight control switch HEADBattery positive voltage
Taillight 47 ± GroundConstantBattery positive voltage
Taillight 48 ± GroundConstantContinuity
Taillight 50 ± GroundConstantContinuity
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE±28
± BODY ELECTRICALPOWER SOURCE
2329 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
(a) Remove the fuse from the junction block and inspect the
connector on junction block side.
Fuse Tester connectionConditionSpecified condition
DEF 1 ± GroundConstantBattery positive voltage
MIR HTR 7 ± GroundIgnition switch ONBattery positive voltage
S/ROOF 13 ± GroundConstantBattery positive voltage
P FR DOOR 15 ± GroundConstantBattery positive voltage
P/SEAT (P) 23 ± GroundConstantBattery positive voltage
DOME 25 ± GroundConstantBattery positive voltage
S±HTR 27 ± GroundIgnition switch ONBattery positive voltage
TV 31 ± GroundConstantBattery positive voltage
ECU±B2 33 ± GroundConstantBattery positive voltage
P FR DOOR 41 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.
(b) Remove the relay from the junction block and inspect the
connector on junction block side.
Relay Tester connectionConditionSpecified condition
Ignition Main 43 ± GroundIgnition switch ONBattery positive voltage
Mirror Heater 47 ± GroundIgnition switch ONBattery positive voltage
Mirror Heater 50 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE0GD±10
I01372
Ignition SwitchRadio Assembly Tweeter
Front Speakers
Rear Speakers
Tweeter
Radio Assembly LEXUS Navigatioin
System Woofer
Power Amplifier
(NAKAMICHI made)
Driver Side Junction Block

RAD NO.2 FuseEngine Room No.1
Junction Block

ECU±B1 Fuse

RAD NO.1 Fuse
Passenger Side
Junction Block

DOME Fuse CD Auto ChangerCD Magazine
Power Amplifier
(PIONEER made)
BE±216
± BODY ELECTRICALAUDIO SYSTEM
2517 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION
The vehicle shown in this illustration is ºGS400º.
All components of ºGS300º other than the ones used for engine are same as ºGS400º.

BE0G0±05
1
CLOCK WILL NOT OPERATEPASSENGER SEAT BELT WARNING LIGHT DOES NOT OPERATE
I04264
Wire Harness Side5
4
3
6
1RAD NO.2 Fuse
DOME Fuse
Combination
Meter
Body ECU
No.2
Ground ACC
+B
PBEW
ILL
E Clock Assembly
± BODY ELECTRICALCLOCK
BE±227
2528 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
CLOCK
TROUBLESHOOTING
HINT:
Troubleshoot the clock according to the table below.
TroubleshootingNo.
Passenger seat belt warning light does not light up.1
Clock will not operate1
Clock loses or gains time2
± 1.5 seconds / day
INSPECT CLOCK CIRCUIT
(See page DI±849)
TROUBLESHOOTING NO.1
(a) Check that the battery positive voltage is 10 ± 16 V.
If voltage is not as specified, replace the battery.
(b) Check that the DOME and RAD NO.2 fuses are not
blown.
If the fuse is blown, replace the fuse and check for short.
(c) Troubleshoot the clock as follows.
HINT:
Inspect the connector on the wire harness side.

Ye s
Ye sNo
No
Is there battery positive voltage between terminal +B and
body ground?
Is there battery positive voltage between terminal ACC and
body ground?
Replace clock.+B wire harness faulty.
Ye sNo
Is there continuity between terminal GND and
body ground?Ground wire harnss faulty. ACC wire harness faulty.
2 CLOCK LOSES OR GAINS TIME
I04264
Wire Harness Side5
4
3
6
1RAD NO.2 Fuse
DOME Fuse
Combination
Meter
Body ECU
No.2
Ground ACC
+B
PBEW
ILL
E Clock Assembly
Ye s
Is there battery positive voltage between terminal +B and
body ground?
Adjust or replace clock.Bellow 10 V
Locate cause and repair, or recharge battery.
Ye s
Is there battery positive voltage between terminal ACC and
body ground?Bellow 10 V
Locate cause and repair, or recharge battery.
BE±228
± BODY ELECTRICALCLOCK
2529 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
TROUBLESHOOTING NO.2
(a) Check that the battery positive voltage is 10 ± 16 V.
If voltage is not as specified, replace the battery.
(b) Inspect the error of the clock.
Allowable error (per day): ± 1.5 seconds
If the error exceeds the allowable error, replace the clock.
(c) Check that the clock adjusting button is sticking in posi-
tion and has failed to return.
If the error exceeds the allowable error, replace the clock.
(d) Troubleshoot the clock as follows.
HINT:
Inspect the connector on the wire harness side.

BE0G1±08
I01374
Ignitioin SwitchClock Assembly
Driver Side Junction Block

SRS ACC Fuse
Passenger Side
Junction Block

DOME Fuse
± BODY ELECTRICALCLOCK
BE±229
2530 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
LOCATION