Problem with alarm and opening bonnet
 

Just got Home after three months away. I tried to start the car but the battery was flat. So got access to the fuse panel to open the front bonnet to get the battery out for charging, however as soon as I put a secondary battery on the car the alarm goes off.

Putting the key in the ignition I get no power to the dash or Windows etc.

Probably doesn't help that the only key I have here has knackered remote function. Any thoughts?

Did you check fuses?

Regards, Markus

All the fuses are fine

Hm, i think the fuse of the alarm system is shot. The alarm module is below the drivers seat and has it's own fuse.

If you replace this fuse, please disconnect the starter battery before and test the system when the drivers seat isn't placed in the car again. So you an check if the fuse gets shot again when you connect the starter battery.

Be quick when you connect the starter battery. Connect plus first and than minus. Not vice versa. And if you want to disconnect the starter battery, you just have to remove minus.

Hope that helps.

Regards, Markus

I have tried again, this time ignoring the alarm and just letting the other battery hopefully feed some power to the battery on the Boxster.

After a few minutes the alarm stopped sounding. However, still no bonnet release or dash lights.

The electronics under the left hand seat then clicked away for a while, then stopped.

Still no signs of life though

Hi Markus
I checked all the fuses which related to the items I could see we're not working. Did not check the alarm fuse. I expect that is a seat out job.

I checked under the seat for dampness, and it's all dry.

Hello Lanark,

the alarm system has a fuse in the alarm modul. To get there you'll need to put the seat out. I suspect the alarm fuse was shot by opening the bonnet via battery from the fuse panel in the drivers footwell. Nothing to do with water below the seat.

Regards, Markus

I take it the broken alarm fuse sits on the output side of the alarm which is why the alarm itself is working ok?