Basic Principle

The control principles of various lights in the lighting system are basically same,and the test thoughts are also roughly same:check the circuit in accordance with the circuit diagram and take the control system of direction indicator lamp for example,and the circuit diagram of direction indicator lamp is shown in Fig.3.10.

Turn on the left turn indicator switch,pin C27 of BCM will receive a low level signal from light switch,and pin B05 of BCM will output a high level signal to left turn indicator and left turn indicator whll illuminate.

Turn on the right turn indicator switch,pin C07 of BCM will receive a low level signal from light switch,and pin B12 of BCM will output a high level signal to right turn indicator and right turn indicator whll illuminate.(https://www.daowen.com)

Fig.3.10 Schematic Diagram of Lighting System