Toyota Tundra Service Manual: Front Fog Light Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives headlight dimmer switch assembly (front fog light switch) information signals and illuminates the front fog lights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

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

Click here

OK:

Front fog light relay (FOG FR) operates (front fog lights turn on).

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

(a) Remove the front fog light relay (FOG FR) from the engine room relay block and junction block.

(b) Inscpect the front fog light relay (FOG FR).

Click here

NG

REPLACE FRONT FOG LIGHT RELAY (FOG FR)

OK

(a) Remove the front fog light relay (FOG FR) from the engine room relay block and junction block.

(b) Disconnect the 3H driver side junction block assembly connector.

(c) Disconnect the A30 fog light assembly LH connector.

(d) Disconnect the A31 fog light assembly RH connector.

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

Standard Voltage:

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

Standard Resistance:

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

OK

(a) Remove the driver side junction block assembly. Click here

*a Component without harness connected (Driver Side Junction Block Assembly)

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

Click here

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

Standard Resistance:

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY