Diesel Data: Automotive Repair

Light Auto Turn Off System

System Outline

1. Normal Lighting Operation


With the light control SW turned to TAIL position, a signal is input into TERMINAL (A) 17 of the body ECU. Due to this signal, the current flowing to TERMINAL 7 of the ECU flows to TERMINAL (A) 17 to TERMINAL 14 of the light control SW to TERMINAL 16 to GROUND, and TAIL relay causes taillights to turn on.


With the light control SW turned to HEAD position, a signal is input into TERMINALS (A) 17 and (A) 23 of the body ECU. Due to this signal, the current flowing to TERMINAL 8 of the ECU flows to TERMINAL (A) 23 to TERMINAL 13 of the light control SW to TERMINAL 16 to GROUND in the headlight circuit, and causes taillight and HEAD relay to turn the lights on. The taillight circuit is same as above.

2. Light Auto Turn Off Operation
With light on and ignition SW turned off (Input signal goes to TERMINAL 15 of the ECU), when the driver's door is opened (Input signal goes to TERMINAL (C) 14 of the ECU), the body ECU operates and the current is cut off which flows from TERMINAL 7 of the ECU to TERMINAL (A) 17 In taillight circuit and from TERMINAL 8 to TERMINAL (A) 23 in headlight circuit.

As a result, all lights are turned off automatically.