One problem related to brake warning switch has been reported for the 1996 Subaru Legacy. The most recently reported issues are listed below.
When car started after having stopped for 3 hours, battery warning light and brake warning light illuminated. Checked brakes/fluid and alternator belt - no problem found. Continued driving; various lights, including "check engine light" continued to go on and off. Car finally stalled on highway and had to be towed to dealer. Alternator replaced.