uk corolla 1998 alarm at random

My 1998 UK Toyota corolla CD automatic has begun a habit of the alarm sounding for no proper reason. I would like to be able to physically  locate the immobiliser , alarm module circuit, and the piezo sounder.

This appears to be a common problem on some vehicles. There may be back up batteries in alarm modules that may require periodic replacement.

The remote control receiver found near the glove box has temporarily been removed and is not related to the problem.

Any information would be useful.

My 1998 UK Toyota corolla CD automatic has begun a habit of the alarm sounding for no proper reason. I would like to be able to physically  locate the immobiliser , alarm module circuit, and the piezo sounder.

This appears to be a common problem on some vehicles. There may be back up batteries in alarm modules that may require periodic replacement.

The remote control receiver found near the glove box has temporarily been removed and is not related to the problem.

Any information would be useful.

I tried to locate the siren, but it appears to be behind the ABS hydraulic unit behind the offside headlight.  I do not want to ditsurb this for investigation until I am sure I am looking in the right place (seems to be where the bleeping sound is comming from).  Do you kow of the best way to locate and remove the siren for replacement.  I am assuming it must be quite labour intensive, as my Toyota main dealer wants £400 to fix the problem.  They have suggested that the battery is in the siren unit itself

Best regards