sebring convertible seat belt question

does any member have a sebring convertible early 2000's. I have thought about using a pair of their buckets in my 67 fastback for the shoulder belt in the seat back feature. Every one I've checked out at the wreckers the shoulder belt wont extend. Do they need power or someone sitting on a sensor or something to unlock the belt. or are these all busted. the cars weren't in a crash so that's not the issue.

Larry