Lucas box behind dash

Hi, do any of you recognise this part ? Found it behind the speedo and instrument cluster. It has a white connector with 5 wires but is sitting there disconnected. In process of fixing my 90 up buy wasn’t sure about connecting it up till I knew what it was for first! I can’t see any reference to it on wiring diagram either. Thanks in advance for any help you can give.

It's the dim dip unit for the headlights part No PRC8123
You don't have to have it fitted without headlights work normally they are expensive around £150+.
Tim

Brilliant, thanks for the help Tim