Toyota Tundra Service Manual: Taillight Circuit

DESCRIPTION

The main body ECU (multiplex network body ECU) receives headlight dimmer switch information signals and illuminates the taillights, license plate lights and front side marker lights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

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

Click here

OK:

Taillight relay (TAIL) operates (taillights turn on).

OK

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

NG

(a) Disconnect the driver side junction block assembly connector.

*a Front view of wire harness connector (to Driver Side Junction Block Assembly)

(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 driver side junction block assembly.

Click here

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

Click here

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

Standard Voltage:

OK

REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU)

NG

REPLACE DRIVER SIDE JUNCTION BLOCK ASSEMBLY