Can anybody confirm what this relay does in a 408, please?

[dwomby]

My 408 has, amongst other changes, an alternator in place of the original dynamo/generator. From the wiring diagram, it seems there were originally 3 relays in the electrical system - horn relay, cooling fan relay and something called 'ballast relay'. My car also has an electronic distributor. Does that render the 'ballast relay' unnecessary and is the 'ballast relay' the one in the righthand wing bay with the electrical distribution board and fuses. You can see there is one Lucas relay in there in this photo. The modern plastic relay and associated wiring on the silver backing board are replacements for the original cooling fan relay which has been removed. Also, is the empty space above the Lucas relay and fuse box the location of the control box/regulator that was needed for the dynamo? Thanks for any help.

David