Page 1953 of 4323

± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1751
1945 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
HINT:
When using the hand±held tester, start the inspection from step 1 and when not using the hand±held tester,
start from step 2.
1 Check headlight control switch using hand±held tester.
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch ON.
CHECK:
According to the display on the tester, read the ºDATA LISTº.
BODY ECU:
ItemMeasurement Item/Display
(Range)Normal ConditionDiagnostic Note
AUTO LIGHT SWLight control switch (AUTO)/ON or
OFF
ON: Light control switch position is
AUTO
OFF: Light control switch position
is not AUTO
±
HEAD LIGHT SWLight control switch (HEAD)/ON or
OFF
ON: Light control switch position is
HEAD
OFF: Light control switch position
is not HEAD
±
TAIL LIGHT SWLight control switch (TAIL)/ON or
OFF
ON: Light control switch position is
TAIL
OFF: Light control switch position
is not TAIL
±
OK:
The indication on the tester switches between ON and OFF in accordance with the light control
switch status.
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±1686).
NG
2 Check light control switch (See page BE±27).
NG Replace light control switch.
OK
Page 1954 of 4323
DI±1752
± DIAGNOSTICSBODY CONTROL SYSTEM
1946 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check wire harness and connector between light control switch and body ECU,
light control switch and body ground (See page IN±35).
NG Repair or replace wire harness or connector.
OK
Proceed to next circuit inspection shown in
problem symptoms table
(See page DI±1686).
Page 1955 of 4323
I03114
A27
Automatic Light
Control Sensor
CLTS Y
R±G
BRCLTB
CLTEBody ECU
12
B6 4
1
34
B6
3
B6 CLTS
CLTB
CLTE
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1753
1947 Author: Date:
2005 SEQUOIA (RM1146U)
Automatic light control sensor circuit
CIRCUIT DESCRIPTION
The body ECU detects the ambient light level outside the vehicle via the automatic light control sensor.
The body ECU turns the headlights ON and OFF based on the ambient light level sensed by the automatic
light control sensor.
WIRING DIAGRAM
DI1OL±28
Page 1956 of 4323

DI±1754
± DIAGNOSTICSBODY CONTROL SYSTEM
1948 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check automatic light control sensor.
When using hand±held tester:
PREPARATION:
(a) Connect the hand±held tester to the DLC3.
(b) Turn the ignition switch and hand±held tester main switch ON.
BODY ECU:
ItemMeasurement Item/Display
(Range)Normal ConditionDiagnostic Note
ILLUMINATE RATEIllumination rate information/
MIN: 0 MAX: 99.99Condition value will be displayed
Normal value: 0.8 ms to 22.0 ms±
CHECK:
The illumination rate value should change within the following range such as when the light sensor is ex-
posed to light or covered by hand.
OK:
0.8 ms to 22.0 ms
HINT:
Time needed for the light sensor to generate one cycle of frequency according to the brightness.
When not using hand±held tester (See page BE±27):
NG Replace automatic light control sensor.
OK
2 Check harness and connector between automatic light control sensor and body
ECU (See page IN±35).
NG Repair or replace wire harness or connector.
OK
Proceed to next inspection shown in problem
symptoms table (See page DI±1686).
Page 1957 of 4323

I28521
1B
1B1
2
7
1B 1F9Y±R
B6
B6 11
8
R±L Instrument Panel J/B
Y±R
W±BHF HU
J8
J/C A
IE16 LOW
HIGH
FLASH Headlight
Dimmer
Switch
W±BC8 Combination Switch
EL HF HU87Body ECU w/ Daytime Running Light:
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1755
1949 Author: Date:
2005 SEQUOIA (RM1146U)
Headlight dimmer switch circuit
CIRCUIT DESCRIPTION
This circuit detects the headlight dimmer switch condition.
w/ daytime running light:
The body ECU detects the headlight dimmer switch position and turns on the DIMMER relay.
The body ECU informs the combination meter of the headlight dimmer switch condition via BEAN.
When the headlight dimmer switch position is HI or FLASH, the HI beam indicator light on the combination
meter comes on.
w/o daytime running light:
When the headlight dimmer switch position is HI or FLASH, the HI beam indicator light on the combination
meter comes on.
When the HI beam headlights come on, current is supplied to the HI beam indicator light on the combination
meter to turn the indicator light on.
WIRING DIAGRAM
DI94U±08
Page 1958 of 4323
I28522
Body ECU
R±L
B6
HF
B6 Instrument Panel J/B
Combination MeterHU 1B
1BY±R
1F
1B21
79
6
1D
AJ8
J/C118
B
R±GIE Headlight
Dimmer
SwitchLOW
HIGH
FLASHHL
HU HF EL 17
87
BR W±B Y±R
C6C6 1712W±B
HIGH Beam Indicator R±G
C8 Combination Switch
16 w/o Daytime Running Light:
R±G
B BB R±G
R±G 11
2
IA5 IA1
R±G
To Head Light RH
To Head Light LH J4
J/C DI±1756
± DIAGNOSTICSBODY CONTROL SYSTEM
1950 Author: Date:
2005 SEQUOIA (RM1146U)
Page 1959 of 4323
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1757
1951 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check headlight dimmer switch (See page BE±27).
NG Replace headlight dimmer switch.
OK
2 Check wire harness and connector between headlight dimmer switch and body
ECU, headlight dimmer switch and body ground (See page IN±35).
NG Repair or replace wire harness or connector.
OK
3 Check apparatus.
CHECK:
Choose the apparatus to be inspected.
w/o Daytime running lightA
w/ Daytime running lightB
B Proceed to next circuit inspection shown in
problem symptoms table (see page DI±1686).
A
Page 1960 of 4323
DI±1758
± DIAGNOSTICSBODY CONTROL SYSTEM
1952 Author: Date:
2005 SEQUOIA (RM1146U)
4 Check wire harness and connector between combination meter and headlight
dimmer switch, combination meter and headlight (See page IN±35).
NG Repair or replace wire harness or connector.
OK
Proceed to next circuit inspection shown in
problem symptoms table
(See page DI±1686).