When ultrasonic sensors ho faulty they trigger with tempurature drop or rise. My first port if call would be to turn off interior sensors and see if that fixes it. Then as said bonnet sensor. You could get it scanned as that would show whats triggered the alarm.
Do you live near a main road, I do and my old Golf MK5 and more recently neighbours car's alarm goes off when a certain loud bus or trucks goes past. on the Mk5 VW just turned the sensitively down, and it solved it.
Its not a cat jumping on the car is it?That can and does set it off...
Quote from: fredgroves on 22 November 2019, 11:03Its not a cat jumping on the car is it?That can and does set it off...Thought about this as well, not sure why they'd suddenly pick on my car, and you'd think the wailing alarm and flashing lights would be a deterrent!
Quote from: sjw on 22 November 2019, 11:21Quote from: fredgroves on 22 November 2019, 11:03Its not a cat jumping on the car is it?That can and does set it off...Thought about this as well, not sure why they'd suddenly pick on my car, and you'd think the wailing alarm and flashing lights would be a deterrent!I can remember reading on a forum a few years back that a GTI owner had a problem with their car alarm going off intermittently. They found a large live spider in their car, and presumably the movement of the spider was picked up by the car’s interior motion sensors. The spider was removed from the car and no more false alarms.