As electronic circuits are used on the vehicle (cooling, charging system), the welding unit ground terminal must be connected as close to the welding point as possible and engine cooling unit 3 and charging system must be disconnected!
If you are going to weld in more points of the chassis, it is necessary to disconnect the battery terminal with cable from the plus (+) battery terminal and connect the disconnected cable to the vehicle frame.
At the same time, the positive battery outlet must be insulated to avoid accidental short circuit.
When reconnecting, do not forget first to disconnect the frame connection and only then connect to the terminal.