Page 1913 of 4323
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1711
1905 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check FOG LIGHT relay (See page BE±34).
NG Replace FOG LIGHT relay.
OK
2 Check fog light switch (See page BE±34).
NG Replace fog light switch.
OK
3 Check wire harness and connector between FOG LIGHT relay and fog light
switch, FOG LIGHT relay and battery, FOG LIGHT relay and body ground
(See page IN±35).
NG Repair or replace wire harness or connector.
OK
4 Check wire harness and connector between fog light switch and body ECU
(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 1914 of 4323
DI±1712
± DIAGNOSTICSBODY CONTROL SYSTEM
1906 Author: Date:
2005 SEQUOIA (RM1146U)
Daytime running light relay circuit
CIRCUIT DESCRIPTION
Power is supplied to the DIMMER and DRL No. 4 relays when the HEAD relay is turned on.
The HEAD relay turns on by turning the light control switch to the TAIL or HEAD position.
The DIMMER relay turns on by turning the headlight dimmer switch to the LOW, HIGH, or FLASH position.
The body ECU determines the light control switch position and turns on the DRL No. 4 and DIMMER relays.
The DRL No. 4 relay and the daytime running light resistor are parallel circuits. If the light control switch is
OFF, electric current flows to body ground via the resistor instead of driving the DRL No. 4 relay. The head-
lights come on and dim according to the amount of resistance.
DI6M3±11
Page 1915 of 4323
I28771
32
2
1
2Body ECU
2
2 L1
G±W2
2 2
Engine Room R/B No. 2R±W
21
21
21 R±L
A
To Body ECU
(HEAD Relay Circuit)B7
R
2F
B 5
EDMAINHEAD RelayDRLIA117
Battery F10
FL Block J1
J/CW±L
W±L
R±L
R±W
R±WW±B G±W
32
1 W±LW
12 A
A
A
2
22
2
12 3
5
B7 W±B
R W±B
R±LL
L 5
3
21
53
12 12 12G
2C 2D16
4 A2
22
2
2 DIMMER Relay Engine Room R/B No. 2 H5
Headlight
LH
16
17 CH±LP RH
H±ON
DIM DRL No. 4 Relay J4
J/CC H6
Headlight RH
H±LP LH
H±LP RL
H±LP LL
IA118 W±B
4Engine Room R/B No. 2
Engine Room J/B
6
LG±R R±B
J2 J/C
W±L
D1 Daytime Running
Light Resistor
J5
J/C
A
EA
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1713
1907 Author: Date:
2005 SEQUOIA (RM1146U)
WIRING DIAGRAM
Page 1916 of 4323
DI±1714
± DIAGNOSTICSBODY CONTROL SYSTEM
1908 Author: Date:
2005 SEQUOIA (RM1146U)
INSPECTION PROCEDURE
1 Check DRL No. 4 relay and DIMMER relay (See page BE±27).
NG Replace DRL No. 4 relay and DIMMER relay.
OK
2 Check wire harness and connector (Daytime running light circuit)
(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 1917 of 4323
I24352
Body ECU
B5KSW
IGU1
Key Unlock Warning Switch
O1
2
Y±G13
A
AJ43
J/C
O
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1715
1909 Author: Date:
2005 SEQUOIA (RM1146U)
Key unlock warning switch circuit
CIRCUIT DESCRIPTION
The key unlock warning switch turns on when the ignition key is inserted into the key cylinder and turns off
when the key is removed.
WIRING DIAGRAM
DI571±11
Page 1918 of 4323
DI±1716
± DIAGNOSTICSBODY CONTROL SYSTEM
1910 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 key unlock warning 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
KEY UNLK WRN SWKey unlock warning switch/ON or
OFFON: Key is in ignition key cylinder
OFF: No key is in ignition key cyl-
inder
±
OK:
The indication on the tester switches between ON and OFF in accordance with the key unlock
warning switch status.
OK Proceed to next circuit inspection shown in
problem symptoms table (See page DI±1686).
NG
2 Check key unlock warning switch (See page BE±24).
NG Replace key unlock warning switch.
OK
Page 1919 of 4323
± DIAGNOSTICSBODY CONTROL SYSTEM
DI±1717
1911 Author: Date:
2005 SEQUOIA (RM1146U)
3 Check wire harness and connector between key unlock warning switch and
body ECU, key unlock warning 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 1920 of 4323
I28517
R±L
B2
Back Door Power Window Control Switch
UP
DOWNB6
BDN 14
15 6
B6BUP
3
5W
P±LB6 21
PWSBody ECU DI±1718
± DIAGNOSTICSBODY CONTROL SYSTEM
1912 Author: Date:
2005 SEQUOIA (RM1146U)
Back door power window switch circuit
CIRCUIT DESCRIPTION
The body ECU detects the condition of the back door power window switch and sends the related information
to the back door ECU via BEAN.
WIRING DIAGRAM
DI572±08