Toyota 4Runner: Headlight (HI-BEAM) Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives headlight dimmer switch information signals, and illuminates the high beam headlight.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

Inspect the fuses and bulbs for circuits related to this system before performing the following inspection procedure.

PROCEDURE

(a) Using the Techstream, perform the Active Test (See page ).

OK:

Running light relay operates (high beam headlights illuminate).

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

(a) Remove the running light relay from the engine room relay block, junction block.

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

Standard Voltage:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Remove the running light relay from the engine room relay block, junction block.

(b) Disconnect the 2C and 2D driver side junction block assembly.

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

Standard Resistance (Check for Open):

Standard Resistance (Check for Short):

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Remove the driver side junction block assembly (See page ).

(b) Remove the main body ECU (multiplex network body ECU) from the driver side junction block assembly.

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

Standard Resistance:

NG

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY

OK

(a) Replace the running light relay.

(b) Check that the daytime running lights operate normally (See page ).

OK:

The daytime running lights operate normally.

OK

END (RUNNING LIGHT RELAY WAS DEFECTIVE)

NG

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)