Taillight Relay Circuit: Description

WARNING: This page is about a different car, the 2007 Lexus ES 350. However, it is still accessible from the selected car via links, so may be relevant.

The main body ECU receives a signal from the light control switch, and turns the taillight relay on.

HINT:

When any of the lights do not illuminate, check the bulb or wire harness that is related to the bulb.
When all of the lights that are related to the TAIL relay do not illuminate and the TAIL fuse is normal, read the light control switch TAIL signal value in the data list and perform the taillight relay active test to determine if the malfunction exists on either the switch side or the relay side.