Right - after the problems Ive just had pal, Im a expert.
1. Does it randomly go of once the engine is started ?
2. Does arming the alarm and setting it off by opening the door, bonnet, tailgate, and waving your hands around inside work?
3. Tape down the bonnet alarm switch, Arm the alarm, and disconnect the battery terminal, the alarm senses its being attacked and should sound. Does it ?
4. Check all connections for corrosion/bad earths.
If you want to know where every thing is Pm me.
I have a few spares from when mine played up before I had it replaced.
(Brand new battery pack for the siren. Spare siren unit. Spare brain, and a wiring loom)
Mine turned out to oringinaly have one fault, then it had two, one was the siren going off when i drove it, which turned out to be corrosion on the brain pcb. Its easy to get inside to have a look. PM me if you want the details.
And the other fault appeared after the brain was sent away for testing/repair it came back and knackered my imobiliser unit.
To repair that was £70 and Id already spent £60 odd.
Time for a new alarm.