2000 LEXUS GS400 relay

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)

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)

I04030
Fuses
Relays 1. DEF H±Fuse
2. ±
3. ±
4. MIR HTR Fuse
A. Ignition Main Relay
B. Mirror Heater Relay
E. Body ECU No.1
Passenger Side Instrument Panel Junction Block
5. ±
6. ±
7. S/ROOF Fuse
8. P FR DOOR Fuse
9. ±
10. ±
11 .
12. P/SEAT (P) Fuse
13. DOME Fuse
14. SEAT HTR Fuse
15. ±
16. TV Fuse
17. ECU±B2 Fuse
18. ±
19. ±
20. ±
21. P FR DOOR Fuse
2
21 34 5
67 8 9
10 11 12 13
14 15 16 17
18 19 20AB
E
C. Defogger Relay
D. Heater Relay
CD
1
BE±20
± BODY ELECTRICALPOWER SOURCE
2321 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)

BE±22
± BODY ELECTRICALPOWER SOURCE
2323 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) ECU±B1 30 ± Ground
ConstantBattery positive voltage
HTR 31 ± GroundConstantBattery positive voltage
FAN MAIN 33 ± GroundConstantBattery positive voltage
CDS FAN 35 ± GroundIgnition switch ONBattery positive voltage
RAD FAN 35 ± GroundIgnition switch ONBattery positive voltage
H±LP R LWR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP L LWR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP R UPR 38 ± GroundLight control switch HEADBattery positive voltage
H±LP L UPR 42 ± GroundLight control switch HEADBattery 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
H±LP 44 ± GroundConstantBattery positive voltage
H±LP 46 ± GroundConstantBattery positive voltage
ST 48 ± GroundConstantContinuity
ST 51 ± GroundConstantBattery positive voltage
EFI MAIN 53 ± GroundConstantContinuity
EFI MAIN 55 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

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.

I05033
BE±24
± BODY ELECTRICALPOWER SOURCE
2325 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
3. INSPECT ENGINE ROOM No.2 RELAY BLOCK CIR-
CUIT
Remove the relay from the relay block and inspect the connec-
tor on relay block side.
Relay Tester connectionConditionSpecified condition
HORN 1 ± GroundConstantBattery positive voltage
HORN 2 ± GroundHorn switch ONContinuity
HORN 4 ± GroundConstantBattery positive voltage
ABS SOL 5 ± GroundConstantBattery positive voltage
ABS SOL 6 ± GroundConstantContinuity
TRC MTR 11 ± GroundConstantBattery positive voltage
ABS MTR 15 ± 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.