Toyota Tundra. Manual — part 2487

Fig. 56: Identifying Headlight Dimmer Switch Connector Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

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

Standard resistance

HEADLIGHT DIMMER SWITCH ASSEMBLY

NG: REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY (see REMOVAL )

OK: Go to next step

3. CHECK HARNESS AND CONNECTOR (HEADLIGHT DIMMER SWITCH - MAIN BODY

ECU AND BODY GROUND)

Tester Connection

Switch Condition

Specified Condition

18 (T) - 12 (EL)

Light control switch Tail

Below 1 ohms

Light control switch HEAD

20 (H) - 12 (EL) Light control switch HEAD

19 (A) -12 (EL)

Light control switch AUTO

4 (BFG) - 3 (LFG) Front fog light switch ON

17 (HF) - 12 (EL)

Dimmer switch High

11 (HU) - 12 (EL)

Dimmer switch Low

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Lighting - Tundra

Fig. 57: Identifying Headlight Dimmer Switch And Main Body ECU Connectors Terminals
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

a. Disconnect the J10 switch connector.

b. Disconnect the J3, J4 and DD ECU connectors.

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

Standard resistance

HEADLIGHT DIMMER SWITCH - MAIN BODY ECU AND BODY GROUND

Tester Connection

Condition Specified Condition

J10-4 (BFG) - J3-28 (FFOG)

Always

Below 1 ohms

J10-19 (A) - J4-21 (A)

J10-20 (H) - J3-17 (HEAD)

J10-18 (T) - J4-23 (TAIL)

J10-17 (HF) - J4-13 (HF)

J10-11 (HU) - DD-13 (HU)

J10-12 (EL) - Body ground

J10-3 (LFG) -Body ground

J10-4 (BFG) - Body ground

Always

10 kohms or higher

J10-19 (A) - Body ground
J10-20 (H) - Body ground

J10-18 (T) - Body ground

J10-17 (HF) - Body ground

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Lighting - Tundra

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR

OK: REPLACE MAIN BODY ECU

HEADLIGHT SIGNAL CIRCUIT

DESCRIPTION

The main body ECU receives a headlight Lo switch information signal from the light control switch, and
illuminates the headlight low beam.

WIRING DIAGRAM

Fig. 58: Identifying Headlight Signal - Wiring Diagram
Courtesy of TOYOTA MOTOR SALES, U.S.A., INC.

INSPECTION PROCEDURE

1. PERFORM ACTIVE TEST BY TECHSTREAM (HEADLIGHT)

a. Operate the Techstream according to the steps on the display and select "Active Test".

Techstream

Main Body ECU

J10-11 (HU) - Body ground

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Lighting - Tundra

MAIN BODY ECU - TECHSTREAM ACTIVE TEST CHART

OK: Headlight low beam turns on / turns off.

NG: Go to step 2

OK: PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS
TABLE

2. INSPECT FUSE (HEAD LL, HEAD LR)

a. Remove the HEAD LL and HEAD LR fuses from the engine room junction block.

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

Standard resistance

FUSE (HEAD LL, HEAD LR)

NG: REPLACE FUSE

OK: Go to next step

3. CHECK HARNESS AND CONNECTOR (HEADLIGHT LOW BULB - BATTERY)

a. for LH:

1. Disconnect the A10 headlight connector.

Tester Display Test Part Control Range Diagnostic Note

Head Light

Headlight

ON or OFF

-

Tester Connection Condition Specified Condition

HEAD LL fuse

Always

Below 1 ohms

HEAD LR fuse

2009 Toyota Tundra

2009 ACCESSORIES AND EQUIPMENT Lighting - Tundra