Toyota Sequoia (2005). Manual - part 490

I28521

1B

1B

1

2

7

1B

1F

9

Y–R

B6

B6

11

8

R–L

Instrument Panel J/B

Y–R

W–B

HF

HU

J8
J/C

A

IE

16

LOW

HIGH

FLASH

Headlight
Dimmer
Switch

W–B

C8 Combination Switch

EL

HF

HU

8

7

Body ECU

w/ Daytime Running Light:

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–1755

1949

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

I28522

Body ECU

R–L

B6

HF

B6

Instrument Panel J/B

Combination Meter

HU

1B

1B

Y–R

1F

1B

2

1

7

9

6

1D

A

J8
J/C

11

8

B

R–G

IE

Headlight
Dimmer
Switch

LOW

HIGH

FLASH

HL

HU

HF

EL

17

8

7

BR

W–B

Y–R

C6

C6

17

12

W–B

 HIGH Beam Indicator

R–G

C8 Combination Switch

16

w/o Daytime Running Light:

R–G

B

B

B

R–G

R–G

11

2

IA5

IA1

R–G

To Head Light RH

To Head Light LH

J4
J/C

DI–1756

–

DIAGNOSTICS

BODY CONTROL SYSTEM

1950

–

DIAGNOSTICS

BODY CONTROL SYSTEM

DI–1757

1951

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 light

A

w/ Daytime running light

B

B

Proceed to next circuit inspection shown in
problem symptoms table (see page 

DI–1686

).

A

DI–1758

–

DIAGNOSTICS

BODY CONTROL SYSTEM

1952

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

).