Forgive me for asking...but did they still use the automated shoulder belts in '92? h:

If yes, then I wouldn't screw around with the electrical systems that regulate the belt movement.
If not, I'd disconnect the wires coming from the seat belt buckle.

My old 91 GTi had the same problem... and I traced it back to a contact switch inside the seat belt buckle. Since the dealer wanted $220 for a new buckle assembly, I just disconnected the wire from the chassis harness. No buzzer, no idiot light.