This is attached to the wiring harness for the power driver bucket seat on my '72 Supreme, but it wasn't connected to anything. Is it for an option I don't have?

 

My first thought was a heated seat/warmer. I have no idea if it was even offered. The other notion was some other type 'function' to the seat. Your seat is a 4 way bucket seat correct? The seat moves UP/DOWN & FWD/BK I would suspect.
Of note is this thread (below).
Evidently there were two 1972 4 Way Bucket seats offered?
Type w/ 2 Cables = 4939203
Type w/ 3 Cables = 9625772
I'm assuming cables refer to wiring cable but I might be incorrect.
Are there any markings on the seat frame, etc. w/ the above identifying numbers?

https://classicoldsmobile.com/forums...-frame-117691/

 

I'm guessing that's for the seat switch that operated the FASTEN SEATBELTS warning light. It was first required on cars built after Jan 1, 1972.

 

Yes, that makes sense what Joe said. 1972 was the first year for that on Olds, I think.

 

Jan 1, 1972 on all cars per Federal law.

 

Dave - Since a FASTEN SEATBELTS warning light is the most logical & likely usage, I suspect you'll find the other wire either running under the carpet somewhere or possibly leading into an area around the center console if you have a center console?
At any rate:
Fasten Seat Belts 1972 Cutlass 442 Hurst Olds
Seatbelt Buzzer Question (72 Cutlass)
FASTEN SEAT BELT warning light option

 

I'll check it out...if it's the seat belt buzzer, it's staying disconnected.

 

I think 2 or 3 cables would be 'drive cables'.

 

Yes, Sir - it may very well be drive cables.

 

Seat belt sensor good chance.
But wasn't that only on the passenger seat?

What about the really rare option?
The automatic seat release?