Can you post a photo of the connector? Might be able to tell if it is genuine or not. Do the wires become part of the main loom or are they on the own? If I was to guess, something like this would be fitted inside the car and most probably behind the dashboard, on either the drivers or passenger's footwell.
Are you by any chance at the Facebook Volvo S40 V40 classic group here:
https://www.facebook.com/groups/972416682830534/ ? There are quite a few people there, with Phase 1 models that might be able to shed some light too.