Morning all. I have a Meta 357T V2-1 alarm fitted.

The power supply fuse went and before I replaced it for some reason I tried the alarm to see if it still worked .
I was able to turn the ignition on and start the bike, immobiliser not working and no siren going off. Surely if the main 12v feed to the alarm is interrupted, as in some one cutting the feed to it should it not activate the alarm and all the bells start to go off?

Just after some advice before I ring the dealer who fitted it and ask them to have a look at it and charge me a fortune.
Thanks for any help.

Kev