Right my alarm isn't going off in the middle of the night, in fact it's not going off at all, the indicators flash but no sound. I have just received a seccond hand siren from an ebay seller and no noise, what's the chances of having 2 faulty ones?

Any other suggestions

The alarm system has its own power supply and the service schedule states that the complete alarm system should be replace every 5 years. The lid (bonnet) switch (F120) and associated fuse are also part of the alarm system and are fitted to the bonnet lock. Have you done a diagnostic scan to see if there are any error codes?

There are no fault codes I'm getting a new siren and convenience module so hopefully that will sort it

There is a back up power supply consisting of two soldered in rechargable batteries on the pcb in the alarm horn casing (I know having dismantled mine!) These won't hold charge after several years and they have to be replaced. Skoda just bins the whole horn...is you want you can go to cpc.co.uk or farnellinone.co.uk and get a set of replacement solder on rechargable batteries.. I unpluged my horn and removed as the alarm was being falsely tripped by the neighbours diesel engined fabia (long story...lots of tech research etc). The alarm and imobiliser still work fine...just no siren...and if you dig deep into the fault codes (no dash lamps lit) is says..can't communicate with horn.... also i waterproofed the end plug of wiring loom... THe horn is under the rear of the car near the petol tank and the beam axle.

I've opened mine up and can't get to the batteries the PCb won't budge, hopefully this new one will work

I've opened mine up and can't get to the batteries the PCb won't budge, hopefully this new one will work

you have to carefully lever the pcb from the side post/clips and remove it as the batteries (green? are in the other side (if memory is working)

I've tried levering like you wouldn't believe! O well if this new one works I'll try a bit harder to disassemble this siren and put some new batteries in, might make a couple of quid back