Horn Circuit [08/2013 - ]: Procedure

WARNING: This page is about a different car, the 2014 Lexus ES 300h. However, it is still accessible from the selected car via links, so may be relevant.

INSPECT HORNS

Press the horn switch and check if the horns sound.

Result

Result	Proceed to
Horns sound	A
Horns do not sound	B

B → See step 3

A: Go to next step

INSPECT INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY

Remove the main body ECU (multiplex network body ECU). Refer to REMOVAL [08/2013 - ] .

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

TEXT IN ILLUSTRATION

Component without harness connected
(Instrument Panel Junction Block Assembly)

Disconnect the 3D instrument panel junction block assembly connector.

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

Standard Resistance

Tester Connection	Condition	Specified Condition
3D-15 - MB-28 (HORN)	Always	Below 1 Ω

NG → See step 5

OK → See step 4

GO TO HORN SYSTEM. Refer to PROBLEM SYMPTOMS TABLE [08/2013 - ]
REPLACE MAIN BODY ECU (MULTIPLEX NETWORK BODY ECU). Refer to REMOVAL [08/2013 - ]
REPLACE INSTRUMENT PANEL JUNCTION BLOCK ASSEMBLY. Refer to REMOVAL [08/2013 - ]