The photos of the black box are from another Bravo with homemade wires, but the black box is factory made in this Bravo model. It is 1990 Bravo EEV2T with variator, electronic ignition, but without turn signals. I guess it can not be a battery, because the horn does not work when the engine is off. Look at the scheme, the wire colors are factory made out there. Maybe it is some kind of rectifier that makes AC from magneto into DC – it is connected to the horn, front lamp and (not directly) to the rear lamp (all are 12V). Or maybe it stabilises the voltage so there are no peaks. I guess both could improve the life span of those components. But how to check what the black box actually does?

Yes, it doesn’t work. I know that, because i have three black boxes. Only one, attached to the electrical system of Bravo, makes the lights and horn work. The other two boxes make no effect on lights and horn. Of course even with a faulty black box the engine still works just fine – it’s only for lights and horn. It is connected to horn, front and rear lamp so it has to do something with their functionality. Of course, seeing other electrical schemes, there is a way to connect horn and light without the black box, but as it is factory made, it has to have some vital function. All of my Bravos have the black box factory made. Only one works, so only one Bravo is fully operative. I’m not good with electric stuff so i don’t know if i will be able to make them work without the black box.