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Audi A3 Alarm

Mate has a 9 month old Audi A3 fitted with the factory alarm. It goes off for no apparent reason - but only after dark.

He's at his place in Spain (minus the car) for the summer, and I'm looking after things here. Luckily, a next door neighbour also has a set of the car keys as I live a short way off and wouldn't hear the alarm. Basically I've been charging the car battery every two weeks.

I read the car owner's manual and you can disable both the motion and ultrasonic sensors via push buttons on the driver's door jam - but this apparently didn't work as it went off again. And simply resetting the alarm with the zapper switches those interrupts back to normal.

I've tried rocking the car with the alarm on and this doesn't set it off - nor does slapping a window hard. Both of which set off the alarm on my car

- which doesn't false trigger.

I've disconnected the battery and will contact the dealer today but wondered if anyone had any fixes?

Reply to
Dave Plowman (News)
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Yes when the battery starts getting cold. The sudden drop in voltage as the temperature falls is seen by the system as a break in attempt. I'd lay a bet that replacing the battery will cure it.

Reply to
Michael

Interesting theory. But a sudden drop in voltage?

Reply to
Dave Plowman (News)

Yes when the interior light comes on the alarm system senses the small and sudden drop in voltage as the doors being opened and off goes the alarm.

Allowances are made for a small drop in voltage taking place over the night but any deficiency at all in the battery will give a much more sudden drop which will confuse the alarm.

It drove(pun intended) me up the wall the first time I had this as the fault was not with the alarm at all which I had replaced three times while trying to find the problem.

Reply to
Michael

It is the only reason I can find for house smoke alarms starting to bleep (low battery warning) in the middle of the night and then stopping in the morning. I am not sure that it is a sudden drop in voltage, just that it is a drop in voltage.

Cheers

Adam

Reply to
ARWadsworth

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