As electronic circuits are used on the vehicle (cooling, ABS and charging systems), the welding unit earthing terminal must be connected as close to the welding point as possible!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 terminal must be insulated to avoid accidental short circuit.However, always disconnect the electronic cooling control unit socket 3 (Fig. A 7381) located in the power generator unit in front of the passenger's seat.When re-connecting, do not forget first to disconnect the frame connection and only then connect to the terminal.