I am pretty sure the lock is mechanical not electrical, but I could be wrong.
Good luck fixing your problem.

 

Well, you should check to convince yourself that the mechanical lock DOES work. The warning switch won't necessarily screw that up.

I don't think 1998 has multi-stage airbags, but if it were a newer car that might cause your airbags to fire at low power rather than high-power.

 

The dealer absolutely refused to replace it under warranty, saying the warranty "only applies if the buckle doesn't fasten and unfasten." So I'm going to have to do this task on my own! I'll start by getting a volt meter either today before work or tomorrow after school. Then I'll post results.

Thanks again for everyone's replies!