BE car alarm

Whenever my car gets too much direct sunlight (especially in the afternoon) my car alarm is triggard. This happens so often now that it is spring that it kills my battery! My favorite local mechanic was baffled. I’m not sure what to do.

Try leaving a window open just a crack.

It may have to do with interior pressure build up which eventually escapes…somewhere.

Like through a weather strip in a single little puff ( imagine your car ‘farting’ at the door weatherstrip ) with enough flex/wiggle of the door to trigger the alarm’s shock sensor.
Other orifices that may be ‘sealed’ can also be route of escape. Like through the door handles. As it escapes the outer handle this may also cause a wiggle enough for the alarm.

Does this only happen with the a/c in the recirculating mode ?
Try setting it in ‘vent’ mode when parking it. If it still seals too tight use the open window.

leaving the windowns cracked hasn’t worked and I haven’t ever had the car on circulate, it is always on vent. I will try cracking them a bit further down though maybe that will help. Thank you.

Well, that was just my first theory/guess as to why such a thing might happen.
In 35 years as an automotive parts man I’ve never encountered that.

Maybe try a fold out sun shade inside the windshield ?

Can you change the sensitivity of the motion sensor ?

Lots of other posters in here should have good guesses…
How 'bout it guys/gals ?

My wife’s car did this, and it took the better part of a year and three dealers’ shops to figure it out. She had a nicked driver’s side door lock actuator wire. When the wire flexed inside the door due to heat (only happened in hot weather…) and touched something metal - short circuit, alarm.

Can you imagine how long an alarm must be going for it to kill a fully charged battery, literaly hours,lucky you have and windows left.