1. The voltmeter should show tension of 0,2 Century.
2. If tension more than 0,2 In, means, the wire has damages or it is unreliably connected to plugs of the generator and the storage battery.
For check of a wire connect the plug "B" and the positive plug of the storage battery an additional wire to a fusible insert.
Check reliability of connection of a wire to plugs, and also be convinced that isolation of a wire is not melted from its overheat.
3. In summary transfer the engine to an idling operating mode. Switch off everything consumers of electric energy and stop the engine.