Concern is likely caused by a sticking door ajar switch. Need a factory capable scan tool that has the ability to communicate with the GEM module, first check this module for codes. If any codes are found, perform applicable pinpoint tests. If do not have a scan tool to pull up this information, heavily lube every door latch and switch and see if the concern is gone. Start with the rear door and rear window hatch. A Factory scanner may be able to disable that system but not sure on that year model. I have disabled theft systems on Ford later models with Ford IDS system. But door sensors are a common problem and lubricating them with rust penetrant or WD40 usally works.