What does the wire under the driver's manual seat of a '95 Dodge Caravan do?

[yablocksthetruth]

This is a manual seat and the wire is connected to the seat though obviously not for seat adjustment purposes.

 

[daniel_weedman]

All it is there for is to recognize that there's somebody in the seat, and how much pressure is on the seat. When you get in an accident, the air bag deploys, but it only goes at a pressure fit for your body. Hence making you safer.