Toyota 4Runner manuals

Toyota 4Runner: Headlight Dimmer Switch Circuit

DESCRIPTION

The main body ECU receives the following signals:

  • Headlight dimmer switch tail, head, AUTO*, high or high flash signal
  • Front fog light switch signal
  • *: w/ Automatic Light Control System

WIRING DIAGRAM


PROCEDURE

1.

READ VALUE USING TECHSTREAM (HEADLIGHT DIMMER SWITCH)

(a) Using the Techstream, read the Data List (See page ).


Main Body

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Dimmer SW

Headlight dimmer switch high signal / ON or OFF

ON: Headlight dimmer switch in high or high flash

OFF: Headlight dimmer switch in low

-

Passing Light SW

Headlight dimmer switch high flash signal / ON or OFF

ON: Headlight dimmer switch in high flash

OFF: Headlight dimmer switch not in high flash

-

Front Fog Light SW

Front fog light switch signal / ON or OFF

ON: Front fog light switch on

OFF: Front fog light switch off

-

Auto Light SW*

Headlight dimmer switch AUTO signal / ON or OFF

ON: Headlight dimmer switch in AUTO

OFF: Headlight dimmer switch not in AUTO

-

Head Light SW (Head)

Headlight dimmer switch head signal / ON or OFF

ON: Headlight dimmer switch in head

OFF: Headlight dimmer switch not in head

-

Head Light SW (Tail)

Headlight dimmer switch tail signal / ON or OFF

ON: Headlight dimmer switch in tail or head

OFF: Headlight dimmer switch not in tail or head

-

  • *: w/ Automatic Light Control System

OK:

The display is as specified in the normal condition column.


OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE


NG

2.

INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY

(a) Remove the headlight dimmer switch (See page ).



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

Standard Resistance:

Tester Connection

Switch Condition

Specified Condition

4 (BFG) - 3 (LFG)

Fog light switch on

Below 1 Ω

11 (HU) - 12 (EL)

Headlight dimmer switch high

Below 1 Ω

Headlight dimmer switch high flash

17 (HF) - 12 (EL)

Headlight dimmer switch high flash

Below 1 Ω

18 (T) - 12 (EL)

Headlight dimmer switch tail

Below 1 Ω

Headlight dimmer switch head

19 (A) - 12 (EL)*

Headlight dimmer switch AUTO

Below 1 Ω

20 (H) - 12 (EL)

Headlight dimmer switch head

Below 1 Ω

4 (BFG) - 3 (LFG)

Fog light switch off

10 kΩ or higher

18 (T) - 12 (EL)

Headlight dimmer switch off

10 kΩ or higher

19 (A) - 12 (EL)*

20 (H) - 12 (EL)

  • *: w/ Automatic Light Control System
Text in Illustration

*A

w/ Automatic Light Control System


NG

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY


OK

3.

CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH ASSEMBLY - MAIN BODY ECU AND BODY GROUND)

(a) Disconnect the F22 headlight dimmer switch connector.

(b) Disconnect the F9 main body ECU connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

F22-4 (BFG) - F9-27 (FFOG)

Always

Below 1 Ω

F22-11 (HU) - F9-5 (HU)

Always

Below 1 Ω

F22-17 (HF) - F9-8 (HF)

Always

Below 1 Ω

F22-18 (T) - F9-30 (TAIL)

Always

Below 1 Ω

F22-19 (A) - F9-28 (A)*

Always

Below 1 Ω

F22-20 (H) - F9-29 (HEAD)

Always

Below 1 Ω

F22-4 (BFG) - Body ground

Always

10 kΩ or higher

F22-11 (HU) - Body ground

Always

10 kΩ or higher

F22-17 (HF) - Body ground

Always

10 kΩ or higher

F22-18 (T) - Body ground

Always

10 kΩ or higher

F22-19 (A) - Body ground*

Always

10 kΩ or higher

F22-20 (H) - Body ground

Always

10 kΩ or higher

F22-12 (EL) - Body ground

Always

Below 1 Ω

F22-3 (LFG) - Body ground

Always

Below 1 Ω

  • *: w/ Automatic Light Control System

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)


NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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