this is from 03 seville, they dont list a sts. the two relays are controlled by the rim or rear integration module. i dont know where it is but if you unplug it, and it stops something is either causing the things to activate, or the module is bad. if it doesnt the wires from the relay to the rim are intermittently shorting.
if you leave the fobs home that should be able to verify that. doesnt seem likely