Originally Posted by John Burt

Its not the trembler thats knackered it's the perimmeter switch, the trembler is internal to the alarm. You dont have to by a new switch from datatool any suitable switch will do, try maplins, oh and it doesn't matter wether the switch is nc or no it's the change of state that triggers the alarm.

The led can be replaced but I' m not sure if you need a 12v one or not, ask datatoll, yet again Maplins will be much cheaper than datatool whenit comes to the replacement - you could even get a different colour one. Don't forget that polarity is important when connecting leds, they won't work otherwise. PS if you have a curvy the best place to mount the led is in the back of the rear light cluster, just drill a small hole in from the back and insert led - looks like the brake light is flashing obviously this precludes the use of colour leds white is best here.