Not sure, as I've never investigated but I'd assume it's either the seatbeat indicator (ie when you're not wearing it) or random wiring for heated seats or the possibility thereof. I'd imagine the first.
I always wear a seatbelt. Do you trust the Alfa electrics to deploy the airbag in the event of a head on, especially if you have a wood wheel!!! In theory you are meant to change the airbag unit every 5 years I think for safety reasons!!!
Just force of habit over the years.......................jump in a a car that i`ve fixed move it round the garage/car park and a quick blag down the road without it on to save getting oil on the customers belt(been doing it for the last 17 years)
So i just jump into my motor and away i go without just comes natural and feels so confined when i do wear it
And i know what happens without a belt and the risks involved afterall i used to do Banger Racing and no how important a good belt/harness is but i just can`t get out of the habit
I have an old car circa 1965 which has only lap belts. Feels very odd and insecure compared to three point belts. Having had a good run round Bruntingthorpe in it recently I can confirm taking corners is not much fun either. I wonder how the '50s formula one racers managed with no belts at all.