Strange beeping sound when parked on slope

[localknoxville]

As the title suggests, I have just noticed a strange beeping sound when I've parked the car on a slope, coming from the rear of the car I think and I don't have rear parking sensors either!

There's no warning lights on dash etc and it's only ever made the beeping sound when it's been parked on a slope for a while

I've never noticed this before, I've started a new job and part of the staff car park is on a slope, so when parking it up, I have the handbrake on and in gear

Is this normal and has it happened to anyone else? I've had 3 S3's before and cant remember any of them ever making this beeping noise before

 

[rupe]

Only thing in the back too beep is the alarm module I think, which it does when the batteries go bad, not sure why it would only do it when on a slope though.Have you noticed any water in the back where it is? the rear washer pipe has a habit of coming apart back their and it will wet the alarm, mine used to pour water out the back when I jacked the front of the car up until I fixed it