The dedicated line (Acc line or 15A line) is used for electrical appliances that need to be connected when the engine is not working, such as radios, cigarette lighters, etc. The ignition switch is separately set to the first gear to supply power, but when the engine is running, the radio still needs to be connected to the ignition instrument indicator light to work at the same time, so the contact structure between the ignition switch knife and the contact needs to be specially designed.
The control switch (contact plate) of the main circuit of the starter control line (ST line or line 50) is usually turned on and off by a magnetic switch. There are three types of wiring: the attracting coil and holding coil of the magnetic switch of the low-power starter can be controlled by the starting gear of the ignition switch; the current of the attracting and holding coil of the high-power starter is also very large (up to 40~80A), easy The “30-50” contact pair of the ablation ignition switch must be equipped with a starter relay (such as Dongfeng, Jiefang and Mitsubishi heavy-duty vehicles); for cars equipped with automatic transmissions, in order to ensure neutral starting, the starting control line (50 line) connected in series to the neutral switch.