Help!! Alarm going off with battery disconnected!

[Anonymous]

I had the battery disconnected yesterday whilst replacing the n/s door trim (airbag out). All went fine.

Woke up this morning with the alarm going off. Car was unlocked in the garage so no wind issues.

Just disconnected the battery again for the other side airbag & the alarm goes off - even though I pulled the positive terminal too!!

What's the problem & how do I stop the damned alarm ???

 

[bcworkz]

The alarm obviously has it's own power supply. It's by design to go off when the battery is disconnected. But only when armed. Not sure how to disarm this one though, I don't have one, just happen to know how it's designed. If you did disarm it, there's some issue with it arming its self, no idea how that would happen.

 

[Anonymous]

I've had the battery disconnected before & it didn't go off.

However, whilst turning the key to position 2 to disarm I found there were no lights etc. - the battery was flat. I thought that might be why it was going off so put it on charge. It's still going off so I've left it to build up more of a charge before I disconnect again.

When tuning the key to position 2 the alarm doesn't turn off straight away - is it supposed to take a while before disarming?

 

[Anonymous]

Ok. I charged the battery some more (can't hurt with the winter demands coming up). Disconnect the battery & the alarm still went off. I left it beeping away & after a while it stopped (either timed out or the back up battery went flat.

I took the airbag out, replaced the membrane (with extra sound proofing as recommended elsewher on this forum) & put it all back together. No alarm on reconnection & (touch wood), no other issues.

 

[vanilla]

Strange with the battery off…I had some alarm trouble before which was from a dodgy bonnet sensor, maybe check yours?

 

[Anonymous]

Well everything had gone quiet with the alarm until tonight.

The car had been parked up all day & when I got back to it the siren was giving little triple beeps at seemingly random intervals. Started ok with no warning lights etc. but then the alarm started going off as I drove along.

I've just disconnected the bonnet switch without success.

I see fuse 30 controls the "Thiefproofing system" & central locking. If I pull this fuse will it disable the siren without other side effects (apart from losing c/l)?

I've disconnected the battery to avoid upsetting the neighbours.

 

[Rossi1001]

Ancient thread I know, but I've just had this exact same problem earlier this week and I cannot find a single other example of this anywhere on this or other forums!

I've been having some central locking issues anyway of late (thread here for this), but after the GM5 not fixing it, I need to get the door panel off this weekend to try to test a new (used) door latch mechanism I have. I also have a new heated screen relay to fit (I had disconnected the battery earlier this week for this task).

This is the first time I've had the alarm go off when I've disconnected the battery, and I've definitely had the battery disconnected on other occasions (including since the central locking went wrong) without it triggering the alarm, though that was perhaps before I had my GM5 module 'fixed' (well eBay guy said he fixed something on it, but I don't know what because it didn't repair my central locking issue).

The neighbours are going to hate me with that going off for god knows how long. Do you think disconnecting the GM5 whilst getting the doorcard off etc should stop the alarm? I haven't fitted it back in place yet, it's just sat connected in the footwell, so that's a fairly easy thing to try. Any other ideas are most welcome!

 

[TriggerFish]

If it helps, the alarm siren is behind the rear bumper, which is pretty easy to remove (no need to raise the car up). You might find it best to unplug the siren for now?

 

[tug]

Replace fuse 10 before anything else. It has blown.

 

[Rossi1001]

Many thanks for both of these tips, I'll let you know how I get on!