NB seat plug connector

I’ve fitted NB seats to my NA unfortunately the guy I bought them from didn’t know much about them, I suspect they are standard Tombstone mk2s tha have been recovered as the leather is like new and I don’t think they came factory in bright red. Anyhow my question is wrt plug in picture, it doesn’t fit the plug in the NA which I think is just speaker connection. As the mk2s don’t have built in speakers I can only imagine it for heat seats or sensor for seatbelt warning. Anyone know for sure?

Just been outside and had a look under my seats. Pretty certain the plug is for the seatbelt sensor

Cheers, I think your right, my NA doesn’t seem to have a warning light, and if it did and it’s not working, then unless it’s a MOT fail I’m ok with out it