the main reason the alarm goes off by itself is usually due to
the doors on the car. the alarm is triggered when the cotnrol system
detects that a door has been opened. There should be 2-3 terminals that line up to make sure the door is closed. In the winter they can get frosted with ice or dirty from salt and road dirt. the contacts get greasy/grimy/dirty over time.
switches don't make a good electrical contact the slightest vibration
can cause them to break contact and trick the security control unit into
thinking that someone has attempted to open the door.
The easiest solution is to clean the contacts on the door switches on both
sliding doors with isoprophol alcohol.
the doors use a plunger type switch that the door closes against.
if either of those switches is loose it couldalso cause the same problem.
clean the contacts on the sliding door and see if the problem goes away. it probably will.
I also like to spray the rubber plunger receivers with a quick coat of silicone grease, this keeps the rubber from getting brittle and makes it less prone ot freezing in the winter.
I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_cd01d4e4178e5a11