Everyonce in a while the seatbelt light will come on when Im driving along. Speed, road condition or corning do not seem to affect it. More or less its just when ever it pleases to come on. I am wearing my seat belt when it comes on and as far as I can tell the problem started when I swapped out my stock seats for leather ones out of another GXL. Did I miss something when I put them in? My CPU has been re-soldered and everything besides the warning beeps work. (Think the thing that makes it beep died) Car is an 86 GXL.

 

You could have a bad connection in the wire at the belt or a bad contact in the belt switch itself.