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The alarm has taken to going off regularly during the night and the indicator flashes 7 times. According to the manual this indicates "tampering with battery cables or cutting emergency key cables". None of that is going on so I'm wondering if anyone has any ideas. The battery is charged at 12.65V which is good and there is zero resistance measured between the battery negative and the chassis. I've scanned all the modules for codes with MES and there are none stored.

TIA!
 

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The alarm has taken to going off regularly during the night and the indicator flashes 7 times. According to the manual this indicates "tampering with battery cables or cutting emergency key cables". None of that is going on so I'm wondering if anyone has any ideas. The battery is charged at 12.65V which is good and there is zero resistance measured between the battery negative and the chassis. I've scanned all the modules for codes with MES and there are none stored.

TIA!
Elearn gives the following.....
Maybe a problem with power, or ground of the alarm/siren module ?
 

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My 147 alarm would go off nights only when it was flipping cold and the battery was on its way out. Your battery is good and it's not been that cold. The fact it's nights only means a) temperature b) damp c) scumbags or foxes.

Zero ohms? That's a perfect super conductor :) . I don't even get a perfect zero touching the two probes of my avo together. Is negative lead connected while you measure battery (-) to chassis?

When my key fob battery started to wane I got random alarms too. No idea why - I get why car battery might cause it.

No help. Sorry Chef😉
 

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Discussion Starter #4
Elearn gives the following.....
Maybe a problem with power, or ground of the alarm/siren module ?
Thanks. The siren works just fine, and I would expect 8 flashes if there were problem with it. I believe the alarm is a function of the body computer and if there were a problem with earth then surely I'd see the body computer misbehaving in other ways. I'm at a loss. I think I'll try disconnecting the battery for a while to see if it's just a software problem.
 

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My 147 alarm would go off nights only when it was flipping cold and the battery was on its way out. Your battery is good and it's not been that cold. The fact it's nights only means a) temperature b) damp c) scumbags or foxes.

Zero ohms? That's a perfect super conductor :) . I don't even get a perfect zero touching the two probes of my avo together. Is negative lead connected while you measure battery (-) to chassis?

When my key fob battery started to wane I got random alarms too. No idea why - I get why car battery might cause it.

No help. Sorry Chef😉
It went off yesterday evening so it isn't a night thing after all. It's been warm and dry recently, and there's only one scumbag in the village but I believe he's doing a semi-regular stint in the loony bin at the moment!
 

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The usual suspects for alarm going off are ultrasonic interior sensors and/or tilt sensors, although that wouldn't correspond with the number of flashes you get......
You could however try disabeling these, as an experiment ;)
I ended up permanently disabling the ultrasonic interior alarm on my 147, as it was more trouble then it;s worth .....
 

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Rebooting the electrics (disconnect battery) had no effect. Tomorrow I shall try reseating the connectors to the body computer. If that doesn't work I shall set it on fire.
 

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Keep us posted - I like detective work.

Does your GT have this "Emergency Key" that could cause the 7 flashes?

Had to google what it was
(you'll need to Ctrl F to find in the page)

A hoover around various terminals maybe. Being a Linux geek you well know the origin of the term "bug"...
That separate unit only applies to the 156.... On the GT and 147 everything is integrated in the bodycomputer, with the only external part being the siren, that is controlled via an encrypted connection by the bodycomputer

just in case you don't have it, here's the elearn doc
btw, could it be a problem with the inbuilt backup battery of the siren ? (see page 17 onwards of alarm.pdf)
 

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Thanks jwq. I'm going to reseat the BC connectors first, then I guess I need to take a look at the siren.
 

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That makes sense. GT's have a bit of a habit of water getting past the window seals and into the body computer and causing corrosion.

Also, from previous discussions here the +ve battery connector plate has a habit of causing weird intermittent problems due to corrosion and cracked busbars. It may be worth taking it apart for inspection and cleaning.
 
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