I’ve heard this problem several times on CarTalk (twice in one show) for 91-94 Mazda Proteges, but never with the correct solution. The seat belt alarm in my Mazda was going off intermittently even though I was securely strapped in and driving. It seemed to be triggered by any slight movement on my part. Pulling on the shoulder strap sometimes made it stop. The problem is the switch which makes an alarm when the automatic shoulder strap is disconnected from the window and retracted. Mazda wants something like $1500 for a new seat belt assembly. Take the cover off the emergency brake console (4 screws). Slide it up the seat belts and park it out of the way and don’t move the shoulder straps until you’ve finished. On the back of the seat belt assembly, carefully pry off the 2" diameter plastic covers of both switches. Then carefully remove both the circuit boards with wires and plug attached. Solder a jumper between the two terminals on the circuit board of the seat belt in question, bending it around the hole. Reassemble, and you’re done.