Toyota Tacoma manuals

Toyota Tacoma 2015-2018 Service Manual: Headlight Dimmer Switch Circuit

Toyota Tacoma 2015-2018 Service Manual / Lighting / Lighting System / Headlight Dimmer Switch Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives the following switch information:

  • Light control switch position is off (DRL OFF), tail, head or AUTO (DRL).
  • Dimmer switch position is high, low or high flash (pass).
  • Front fog light switch position is on or off.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

CAUTION / NOTICE / HINT

NOTICE:

If the main body ECU (multiplex network body ECU) is replaced, refer to Registration (See page ).*1

  • *1: w/ Smart Key System

PROCEDURE

1.

READ VALUE USING TECHSTREAM

(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 / Data List.

(e) According to the display on the Techstream, read the Data List.

Main Body

Tester Display

Measurement Item/Range

Normal Condition

Diagnostic Note

Dimmer SW

Dimmer switch high position signal/ON or OFF

ON: Dimmer switch in high or high flash (pass) position

OFF: Dimmer switch in low position

-

Passing Light SW

Dimmer switch high flash (pass) position signal/ON or OFF

ON: Dimmer switch in high flash (pass) position

OFF: Dimmer switch not in high flash (pass) position

-

Front Fog Light SW

Front fog light switch signal/ON or OFF

ON: Front fog light switch ON

OFF: Front fog light switch off

w/ Fog Light

Auto Light SW

Light control switch AUTO position signal/ON or OFF

ON: Light control switch in AUTO position

OFF: Light control switch not in AUTO position

w/ Automatic High Beam System

Head Light SW

Light control switch head position signal/ON or OFF

ON: Light control switch in head position

OFF: Light control switch not in head position

-

Tail Light SW

Light control switch tail position signal/ON or OFF

ON: Light control switch in tail or head position

OFF: Light control switch in neither tail nor head position

-

OK:

Normal conditions listed above are displayed.

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

2.

INSPECT HEADLIGHT DIMMER SWITCH ASSEMBLY

HINT:

Inspect the items that did not change as a result of monitoring the Data List.

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

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

Standard Resistance:

Light Control Switch

Tester Connection

Switch Condition

Specified Condition

18 (T) - 15 (EL)

Light control switch off

10 kΩ or higher

19 (H) - 15 (EL)

10 kΩ or higher

20 (A) - 15 (EL)

10 kΩ or higher

18 (T) - 15 (EL)

Light control switch in tail position

Below 1 Ω

18 (T) - 15 (EL)

Light control switch in head position

Below 1 Ω

19 (H) - 15 (EL)

Below 1 Ω

20 (A) - 15 (EL)*1

Light control switch in AUTO position

Below 1 Ω

Dimmer Switch

Tester Connection

Switch Condition

Specified Condition

14 (HU) - 15 (EL)

Dimmer switch in low position

10 kΩ or higher

14 (HU) - 15 (EL)

Dimmer switch in high position

Below 1 Ω

17 (HF) - 15 (EL)

Dimmer switch in high flash position

Below 1 Ω

Fog Light Switch (w/ Fog Light)

Tester Connection

Switch Condition

Specified Condition

9 (BFG) - 8 (LFG)

Fog light switch off

10 kΩ or higher

9 (BFG) - 8 (LFG)

Fog light switch ON

Below 1 Ω

  • *1: w/ Automatic High Beam System

OK:

Headlight dimmer switch assembly is normal

Text in Illustration

*a

Component without harness connected

(Headlight Dimmer Switch Assembly)

NG

REPLACE HEADLIGHT DIMMER SWITCH

OK

3.

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

(a) Disconnect the C11 headlight dimmer switch assembly connector.

(b) Disconnect the M6 main body ECU (multiplex network body ECU) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

C11-9 (BFG) - M6-26 (FFOG)

Always

Below 1 Ω

C11-14 (HU) - M6-24 (HU)

Always

Below 1 Ω

C11-17 (HF) - M6-10 (HF)

Always

Below 1 Ω

C11-18 (T) - M6-22 (TAIL)

Always

Below 1 Ω

C11-19 (H) - M6-12 (HEAD)

Always

Below 1 Ω

C11-20 (A) - M6-8 (A)

Always

Below 1 Ω

C11-9 (BFG) - Body ground

Always

10 kΩ or higher

C11-14 (HU) - Body ground

Always

10 kΩ or higher

C11-17 (HF) - Body ground

Always

10 kΩ or higher

C11-18 (T) - Body ground

Always

10 kΩ or higher

C11-19 (H) - Body ground

Always

10 kΩ or higher

C11-20 (A) - Body ground

Always

10 kΩ or higher

C11-15 (EL) - Body ground

Always

Below 1 Ω

C11-8 (LFG) - Body ground

Always

Below 1 Ω

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

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