Toyota 4Runner: Taillight Relay Circuit

Toyota 4Runner Service Manual / Vehicle Exterior / Lighting (ext) / Lighting System / Taillight Relay Circuit

DESCRIPTION

The main body ECU receives headlight dimmer switch information signals, and illuminates the clearance lights, taillights and license plate lights.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

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

PROCEDURE

1.	PERFORM ACTIVE TEST USING TECHSTREAM (TAILLIGHT RELAY)

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

Main Body

Tester Display	Test Part	Control Range	Diagnostic Note
Taillight Relay	Taillight relay	ON/OFF	-

OK:

Taillight relay operates (taillights illuminate).

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

2.	CHECK HARNESS AND CONNECTOR (BATTERY - MAIN BODY ECU)

(a) Remove the main body ECU (See page ).

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

Standard Voltage:

Tester Connection	Condition	Specified Condition
A-14 (TRLY) - Body ground	Always	11 to 14 V

Text in Illustration

*a	Front view of wire harness connector (to Main Body ECU)

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

REPAIR OR REPLACE HARNESS OR CONNECTOR

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