Toyota Venza: Light Control Switch Circuit

Toyota Venza Service Manual / Lighting (ext) / Lighting System / Light Control Switch Circuit

DESCRIPTION

The main body ECU (driver side junction block assembly) receives the following switch information:

Light control switch position off, tail, head or AUTO
Dimmer switch position high, low or high flash (pass)
Fog light switch position on or off

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the ignition switch to ON.

(d) Enter the following menus: Body Electrical / Main Body / Data List.

(e) Read Data List according to the display on the Techstream.

Main Body

Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
Dimmer Hi 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	-
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	-
Head Light SW (Head)	Light control switch head position signal/ON or OFF	ON: Light control switch in head position OFF: Light control switch not in head position	-
Head Light SW (Tail)	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.

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

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	Condition	Specified Condition
12 (EL) - 18 (T)	OFF	10 kΩ or higher
18 (T) - 19 (A)	OFF	10 kΩ or higher
19 (A) - 20 (H)	OFF	10 kΩ or higher
12 (EL) - 18 (T)	TAIL	Below 1 Ω
12 (EL) - 18 (T)	HEAD	Below 1 Ω
18 (T) - 20 (H)	HEAD	Below 1 Ω
12 (EL) - 19 (A)	AUTO	Below 1 Ω

Dimmer Switch

Tester Connection	Condition	Specified Condition
11 (HU) - 12 (EL)	LOW	10 kΩ or higher
11 (HU) - 12 (EL)	HIGH	Below 1 Ω
12 (EL) - 17 (HF)	HIGH FLASH	Below 1 Ω

Fog Switch

Tester Connection	Condition	Specified Condition
3 (LFG) - 4 (BFG)	OFF	10 kΩ or higher
3 (LFG) - 4 (BFG)	ON	Below 1 Ω

OK:

Headlight dimmer switch assembly is normal.

Text in Illustration

*a	Component without harness connected: (Headlight Dimmer Switch Assembly)

REPLACE HEADLIGHT DIMMER SWITCH ASSEMBLY

3.	CHECK HARNESS AND CONNECTOR (MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY - HEADLIGHT DIMMER SWITCH ASSEMBLY

(a) Disconnect the D33 headlight dimmer switch assembly connector.

(b) Disconnect the D49, D50 and 2N main body ECU (driver side junction block assembly) connectors.

Standard Resistance:

Tester Connection	Condition	Specified Condition
D33-4 (BFG) - D49-28 (FFOG)	Always	Below 1 Ω
D33-11 (HU) - 2N-2 (HU)	Always	Below 1 Ω
D33-17 (HF) - D50-13 (HF)	Always	Below 1 Ω
D33-18 (T) - D50-23 (TAIL)	Always	Below 1 Ω
D33-19 (A) - D50-21 (A)	Always	Below 1 Ω
D33-20 (H) - D49-17 (HEAD)	Always	Below 1 Ω
D33-3 (LFG) - Body ground	Always	Below 1 Ω
D33-4 (BFG) - Body ground	Always	10 kΩ or higher
D33-11 (HU) - Body ground	Always	10 kΩ or higher
D33-17 (HF) - Body ground	Always	10 kΩ or higher
D33-18 (T) - Body ground	Always	10 kΩ or higher
D33-19 (A) - Body ground	Always	10 kΩ or higher
D33-20 (H) - Body ground	Always	10 kΩ or higher
D33-12 (EL) - Body ground	Always	Below 1 Ω

Text in Illustration

*a	Front view of wire harness connector (to Headlight Dimmer Switch Assembly)
*b	Front view of wire harness connector (to Main Body ECU (Driver Side Junction Block Assembly))
*c	Front view of wire harness connector (to Main Body ECU (Driver Side Junction Block Assembly))
*d	Front view of wire harness connector (to Main Body ECU (Driver Side Junction Block Assembly))

REPLACE MAIN BODY ECU (DRIVER SIDE JUNCTION BLOCK ASSEMBLY)

REPAIR OR REPLACE HARNESS OR CONNECTOR

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