Last Modified: 11-29-2007 1.6 J
Service Category: Vehicle Exterior Section: Lighting (ext)
Model Year: 2008 Model: Sequoia Doc ID: RM000002WL6005X
Title: LIGHTING (EXT): LIGHTING SYSTEM: DESCRIPTION (2008 Sequoia)

Headlight (HI-BEAM) Circuit

DESCRIPTION

The main body ECU receives light control switch and dimmer switch information signals from the headlight dimmer switch, and illuminates the headlight high beam.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

PERFORM ACTIVE TEST USING TECHSTREAM (HEADLIGHT (HIGH))

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Main Body / Active Test / Head Light Hi

(e) Check that the headlight (high) turns on/off.

Main Body

Tester Display

Test Part

Control Range

Diagnostic Note

Head Light Hi

Headlight (High)

ON or OFF

-

OK:

Headlight (High) turns on/off.

OK

2.

INSPECT FUSE (HEAD LH, HEAD RH)

(a) Remove the HEAD LH and HEAD RH fuse from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

HEAD LH fuse

Always

Below 1 Ω

HEAD RH fuse

Always

Below 1 Ω

(c) Reinstall the HEAD LH and HEAD RH fuses.

OK

3.

INSPECT HEADLIGHT (HIGH) BULB

(a) Temporarily replace the headlight (high) bulb with a new or normally functioning one LIGHTING (EXT): HEADLIGHT ASSEMBLY: DISASSEMBLY (2008 Sequoia)+ .

(b) Check that the headlight (high) come on.

OK:

Headlight (high) come on.

OK

4.

CHECK HARNESS AND CONNECTOR (HEADLIGHT (HIGH) BULB - HEADLIGHT DIMMER RELAY)


(a) for LH:

(1) Disconnect the A10 headlight (high) LH connector.

(2) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A10-2 - Body ground

Light control switch HEAD, dimmer switch High

11 to 14 V

Light control switch HEAD, dimmer switch except High

Below 1 V

(3) Reconnect the headlight (high) LH connector.

(b) for RH:

(1) Disconnect the A11 headlight (high) RH connector.

(2) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

A11-2 - Body ground

Light control switch HEAD, dimmer switch High

11 to 14 V

Light control switch HEAD, dimmer switch except High

Below 1 V

(3) Reconnect the headlight (high) RH connector.

OK

5.

INSPECT HEADLIGHT DIMMER RELAY (DIM)


(a) Remove the headlight dimmer relay from the engine room relay block.

(b) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

3 - 5

When battery voltage is not applied to terminals 1 and 2

10 kΩ or higher

When battery voltage is applied to terminals 1 and 2

Below 1 Ω

(c) Reinstall the headlight dimmer relay.

OK

6.

CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - HEAD RELAY)


(a) Remove the headlight dimmer relay from the engine room relay block.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

Headlight dimmer relay terminal 1 - Body ground

Light control switch HEAD, dimmer switch Low

11 to 14 V

Headlight dimmer relay terminal 3 - Body ground

Light control switch HEAD, dimmer switch Low

11 to 14 V

(c) Reinstall the headlight dimmer relay.

OK

7.

CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - HEADLIGHT (HIGH) BULB)

(a) Remove the headlight dimmer relay from the engine room relay block.

(b) for LH:

(1) Disconnect the A10 headlight (high) LH connector.

(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

Headlight dimmer relay terminal 5 - A10-2

Always

Below 1 Ω

Headlight dimmer relay terminal 5 - Body ground

Always

10 kΩ or higher

(3) Reconnect the headlight (high) LH connector.

(c) for RH:

(1) Disconnect the A11 headlight (high) RH connector.

(2) Measure the resistance according to the value(s) in the table below.

Standard Resistance:

Tester Connection

Condition

Specified Condition

Headlight dimmer relay terminal 5 - A11-2

Always

Below 1 Ω

Headlight dimmer relay terminal 5 - Body ground

Always

10 kΩ or higher

(3) Reconnect the headlight (high) RH connector.

(d) Reinstall the headlight dimmer relay.

OK

8.

CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER RELAY - MAIN BODY ECU)


(a) Disconnect the DB main body ECU connector.

(b) Measure the voltage according to the value(s) in the table below.

Standard Voltage:

Tester Connection

Switch Condition

Specified Condition

DB-16 - Body ground

Light control switch HEAD

11 to 14 V

(c) Reconnect the main body ECU connector.

OK