Some on the BB have recommended "Wesco" seat belts. Use the Search function with that key word and some threads will pop up.
If you're brake warning light is on and all seems to be working ok, it could be a stuck brake pressure light switch. Pop open the hood and just to the rear of the SPICA fuel filter, on the passenger side of the engine bay, you'll find some hard tubing that is screwed into a small black manifold. At the top center of that manifold is a switch with an orange wire. Pull the wire from the switch to create an open circuit and see if the brake light goes out. If it does, the switch is stuck in the closed position.
I have the same problem with my brake dash light always on...I pulled the orange wire and the light went out. Is it possible to fix it so it isn't stuck in the closed position?