Ok Pete.
I think the first place to start is to check the plug fits the black box, stay with me here!! There are 2 types and both will slot into each other but the pins are different spacings. Check the blank spaces are in the same place.
If that is as it should be. Connecting to a battery will do the job, however you need to know the power to the motor colour and the headlamp colour and join them together, because the power goes from the switch to the motor but when it reaches it's up position it transfers the power to the bulb. Down is reverse but a capicitor holds enough charge to power the motor down.
Now the colours are not in the Suzuki manual but I did draw them on the old site.
I actually have the diagram here but amnot able to get it uploaded on this site at the moment.
Yellow/black main beam indicator.
black/white earth
white dipped beam
yellow main beam
grey side light
red/yellow positive when lights on
Red /black power from ignition feed.

Good luck