Early morning alarm

Jamie25

Member
 Gloucestershire
My '03 plate 3.0 had a slightly dodgy alarm that went off randomly a few times a few months ago. I disconnected the under bonnet switch and that seemed to sort the issue.

However about two weeks ago the alarm went off at the crack of dawn, and has done so five or six times since then, but always at first light and only then. I live in a rural area with no one passing by. There are no animal foot prints on the car and no sign of spiders or the like living in the car that might be setting it off as they move about more with the light.

I've tested the battery and it's 12.5v stationary. It gets driven daily, pretty much.

Any thoughts?

I'm struggling to figure this one out and I've done LOTS of forum and Internet searching.
 
There do seem to be some strange & random occasions where the alarm goes off. I guess you read through this one https://z4-forum.com/forum/viewtopic.php?f=3&t=120992&hilit=Alarm?
As for you it seems to be at the crack if dawn have you tried parking you car the other way round just in case the sunrise is causing it to go off? Or maybe double clicking to deactivate the internal sensors? You've already tried the obvious things so I'm sorry I can't really suggest anything else. The thing is these cars are getting a bit long in the tooth now & unfortunately the odd electrical gremlins are starting to show.
 
Do you have a neighbor that leaves for work around that time? Could be interference form a garage door opener, house or car alarm signals or such.
 
Mine has gone off a few times the past year with the sun on it. I"ve not a clue why. Never happens on cold days. :?
 
oldgitdave said:
There do seem to be some strange & random occasions where the alarm goes off. I guess you read through this one https://z4-forum.com/forum/viewtopic.php?f=3&t=120992&hilit=Alarm?
As for you it seems to be at the crack if dawn have you tried parking you car the other way round just in case the sunrise is causing it to go off? Or maybe double clicking to deactivate the internal sensors? You've already tried the obvious things so I'm sorry I can't really suggest anything else. The thing is these cars are getting a bit long in the tooth now & unfortunately the odd electrical gremlins are starting to show.
I mist that bit in the other thread about disabling the interior sensor. I am pretty sure that is the one that missbehaves on mine on hot days. I will try the double click and check the red light next time it happens. :)
 
Definately not neighbours as the only one who passes leaves later. I'm trying the double click thing tonight so we'll see how that goes.

Interesting point about parking the other way around, I shall give that a go but actually, thinking about it I don't think it's light as it's literally first light, before sunrise when it's really dim.

Always tricky when it's intermittent. :?
 
Also, if it was a neighbour it would probably remain the same time every day, but if it's to do with light, it'll happen a little bit later every morning.
 
After spending a couple of hours stripping out the centre consul this afternoon I thought I'd post an update and ask a further question....

So double clicking the lock button on the fob seems to have worked (when I remember to do it) so that suggests that it's likely the interior motion sensor or the tilt sensor at fault. I stupidly stripped out the centre consul to get to the tilt sensor only to find there wasn't one. It must be in the rear wheel arch with the siren. There was a good and bad side to this - I'd been meaning to strip out the centre consul to address a squeak, which I've hopefully now done, although I managed to damage some clips on the upper 'switch' panel so I've got to find a replacement now!

I've been trying to locate the interior motion sensor but I'm really struggling. I was hoping to unplug each sensor to see if that stopped the issue and then replace. But as the tilt sensor is part of the siren unplugging that wont tell me anything, which leaves only the motion sensor.

I've tested the batter again this afternoon. After sitting for three hours I popped the boot open using the fob and measured 12.75V, so I still don't think it's the battery.
 
Does nobody know where the interior motion sensor is? Seems like the Internet doesn't, or at least I can't find it! :headbang:
 
If its installed (its an option) it is in the center console under the "phone" buttons.
 
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