The Alarm batteries only charge with the key on. If your charger is capable of 25 amps turn the key on with the charger attached. I am unclear as to what you mean by the alarm in trunk. There is only one security alarm. Is it a sound or a warning on the dash you are seeing? The siren for the alarm is in the right front wheel well. There are modules in the boot. Can you describe the sound or record it and attach it to this? Colin
Can you tell which side of the trunk it is coming from? And how loud? Car horn loud? Or key in buzzer loud? Colin
Sounds like there is a relay behind one of the panels staying powered up. You can isolate the side and remove the panels pretty easily. Once the relay is located we can figure out what the relay does.