Alarm sometimes makes noise and sometimes deosn't

[Good Soil (Pete)]

V8V Roadster - Roof up.....hop out shut the door blip the alarm as a I walk away. Today the alarm makes a little high pitch noise. Normally I don't hear any noise from the alarm. Sometimes it makes a high pitch squeak when I lock it and other times it doesn't.

Checked all the doors were shut correctly and it all looked good............anyone know why it might have done it?

[rick-derby-]

I would suspect the battery is failing in the alarm sounder, not a common problem but have seen it in about 5% of cars around 4 years old

[Good Soil (Pete)]

Merci Merci!