heater LEXUS GS400 2000 Service User Guide

I03731
I02400
AC±68
± AIR CONDITIONINGSERVOMOTOR
2753 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
2. REMOVE AIR MIX SERVOMOTOR (Driver Side)
(a) Remove these parts:
(1) No.1 under cover
(2) No.1 safety pad (See page BO±91)
(b) Remove the air mix servomotor.
(1) Disconnect the connector.
(2) Remove the 3 screws and servomotor.
3. REMOVE AIR MIX SERVOMOTOR (Passenger Side)
(a) Remove heater radiator (See page AC±55).
(b) Remove the air mix servomotor.
(1) Disconnect the connector.
(2) Remove the 3 screws and servomotor.

Z19533
32 1
541
43 2
5AC0XQ±01
I050271 2
5
1235
3
N23635
3
2
15
4
± AIR CONDITIONINGRELAY
AC±79
2764 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
RELAY
INSPECTION
1. INSPECT HEATER MAIN RELAY
(Marking: HTR) CONTINUITY
ConditionTester connectionSpecified condition
Constant2 ± 4
1 ± 3Continuity
Apply B+ between
terminals 1 and 3.5 ± 4Continuity
If continuity is not as specified, replace the relay.
2. INSPECT MAGNETIC CLUTCH RELAY
(Marking: A/C COMP) CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
3. INSPECT No.2 COOLING FAN RELAY
(Marking: FAN NO.2) CONTINUITY
ConditionTester connectionSpecified condition
Constant1 ± 2
3 ± 4Continuity
Apply B+ between
terminals 1 and 2.3 ± 5Continuity
If continuity is not as specified, replace the relay.
4. INSPECT No.3 COOLING FAN RELAY
(Marking: FAN NO.3) CONTINUITY
Check the relay in the same way as for ºMAGNETIC CLUTCH
RELAYº.

I01294
Repair Point
Broken
Wire
Marking Tape
I01295
I04115
78
I04269
12 13
BE±110
± BODY ELECTRICALDEFOGGER SYSTEM
2411 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
8. IF NECESSARY, REPAIR DEFOGGER WIRE
(a) Clean the broken wire tips with grease, wax and silicone
remover.
(b) Place the masking tape along both sides of the wire for
repair.
(c) Thoroughly mix the repair agent (Dupont paste No.
4817).
(d) Using a fine tip brush, apply a small amount of the agent
to the wire.
(e) After a few minutes, remove the masking tape.
(f) Do not repair the defogger wire for at least 24 hours.
9. w/ Mirror heater (w/o Driving position memory):
INSPECT MIRROR DEFOGGER OPERATION
(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.
10. w/ Mirror heater (w/ Driving position memory):
INSPECT MIRROR DEFOGGER OPERATION
(a) Connect the positive (+) lead from the battery to terminal
12 and the negative (±) lead to terminal 13.
(b) Check that the mirror becomes warm.
HINT:
It will take a short time for the mirror to become warm.

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)

BE0GH±10
I01370
Ignition Switch
Seat Heater SwitchPassenger Side Junction Block
SEAT±HTR Fuse
Seat Heater CushionSeat Heater Back
Seat Heater Cushion Inner
BE±184
± BODY ELECTRICALSEAT HEATER SYSTEM
2485 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
SEAT HEATER SYSTEM
LOCATION

BE0GI±07
I04180e±6±2±H
I04181
4 6
L
R Switch
L Switch
I04182
Seat back connector ºAº
Seat cushion
inner
connector ºBº
± BODY ELECTRICALSEAT HEATER SYSTEM
BE±185
2486 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
INSPECTION
1. INSPECT SEAT HEATER SWITCH CONTINUITY
Switch positionTester connectionSpecified condition
Right side3 ± 4 ± 6Continuity
OFF±No continuity
Left side2 ± 4 ± 6Continuity
Illumination circuit1 ± 5Continuity
If continuity is not as specified, replace the switch.
2. INSPECT SEAT HEATER INDICATOR LIGHT OPERA-
TION
(a) Connect the positive (+) lead from the battery to terminal
6 and the negative (±) lead to terminal 4.
(b) Push the seat heater switch Right or Left side and check
that the indicator light lights up.
If operation is not as specified, replace the switch and inspect
the circuits connected to other parts.
3. INSPECT SEAT HEATER CUSHION CONTINUITY
(a) Heat the thermostat with a light.
(b) Inspect the seat heater cushion continuity between termi-
nals, as shown.
Tester connectionConditionSpecified condition
A2 ± B1ConstantContinuity
A1 ± A2Seat heater temperature below 25 °C (77 °F)Continuity
B1 ± B2Seat heater temperature above 45 °C (113 °F)No continuity
If continuity is not as specified, replace the seat cushion pad.

I01824
Wire Harness Side
e±2±1
2 1
I01824
Wire Harness Side
e±2±1
2 1 BE±186
± BODY ELECTRICALSEAT HEATER SYSTEM
2487 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
4. INSPECT SEAT HEATER CUSHION CONTINUITY
Inspect the seat heater inner cushion and front cushion continu-
ity between terminals, as shown.
Tester connectionConditionSpecified condition
1 ± Body groundSeat heater switch ONBattery positive volatage
If continuity is not as specified, replace the seat back pad.
5. INSPECT SEAT BACK CONTINUITY
Inspect the seat back continuity between terminals, as shown.
Tester connectionConditionSpecified condition
2 ± Body groundConstantContinuity
If continuity is not as specified, replace the seat back pad.

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.

I05029
1 23 4 5
6 78 9 10
± BODY ELECTRICALPOWER SOURCE
BE±29
2330 Author: Date:
2000 LEXUS GS300/GS400 (RM718U)
6. INSPECT PASSENGER COWL SIDE RELAY BLOCK
CIRCUIT
Remove the relay from the relay block and inspect the connec-
tor on relay block side.
Relay Tester connectionConditionSpecified condition
DEF 1 ± GroundConstantBattery positive voltage
HEATER 6 ± GroundConstantBattery positive voltage
If the circuit is not as specified, inspect the circuits connected
to other parts.

BE±10
± BODY ELECTRICALTROUBLESHOOTING
2311 Author: Date:
2000 LEXUS GS300/GS400 (RM718U) Malfunction indicator light does not light up.
1. Bulb
2. Meter Circuit Plate
3. Wire Harness
4. ECM (2JZ±GE)
5. ECM (1UZ±FE)±
BE±92
±
DI±1
DI±156
Fuel level warning light does not light up.
1. Bulb
2. Fuel level warning sensor
3. Meter Circuit Plate
4. Wire Harness±
±
BE±92
±
ELECTRIC TENSION REDUCER SYSTEM
SymptomSuspect AreaSee page
Tension Reducer does not operate.
(Driver's and Passenger's)1. ECU±IG Fuse
2. Wire HarnessBE±21
±
Tension Reducer does not operate.
(Only one side)1. Buckle Switch
2. Tension Reducer Solenoid
3. Wire HarnessBE±92
BE±92
±
DEFOGGER SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
Rear window defogger does not operate.
1. HTR Fuse
2. DEF M±Fuse
3. Defogger Relay Circuit
4. Defogger Switch (in A/C Panel Switch)
5. Defogger Wire
6. Wire Harness
7. Body No.1 ECUBE±21
BE±21
DI±812
BE±108
BE±108
±
DI±776
Mirror defogger does not operate.
1. MIR±HTR Fuse (Passenger SIde J/B)
2. Mirror Heater Relay
3. Mirror Heater
4. Wire HarnessBE±21
BE±108
BE±108
±
POWER WINDOW CONTROL SYSTEM
This system uses the multiplex communication system, so check diagnosis system of the multiplex commu-
nication system before you proceed with troubleshooting.
SymptomSuspect AreaSee page
All the power windows do not operate.
(Power Door Lock System is normal.)
1. PWS terminal circuit
2. Power Window Master Switch
3. Wire Harness
4. Driver Door ECU
5. Body No.1 ECUDI±818
BE±117
±
DI±856
DI±776
Only the driver's window does not operate.
1. Power Window Master Switch
2. Power WIndow Switch
3. Power Window Motor
4. Wire HarnessBE±117
BE±117
BE±117
±
ºWindow lock functionº does not operate.1. Power Window Master SwitchBE±117
Window does not operate with power window master switch.
(Manual or Automatic operation can be performed.)TROUBLESHOOTING NO.1BE±111
Remote control of all windows (Except driver's) does not functions
with master switch.
(Windows operate normally with each of master switch.)
TROUBLESHOOTING NO.2BE±111