I have a 2001 Vectra and for a few weeks my offside headlight came on after a short while after turning them on. Now it doesnt come on at all. So, I popped the bonnet and thinking it was a loose connection, fiddled with it. All of the sudden the alarm went off. In a panic I disconnected the battery and the powersounder started. This lasted for about 20 seconds and stopped. I tried re-connecting the battery but the alarm sounded again so I left it off and that's how it stays. Can anyone tell me why the alarm went off in the first place? and what can I do to stop the alarm sounding? I have spent the last 6 hours trawling the forum for help but there is nothing specific.