I had left a post before about this issue, now the update;
Initially the Dealer asked for $450+ to check and change the Alarm Horn, saying it is hidden is a place that is difficult to reach. I have the Audi-Bentley manual CD/DVD, so I looked inside. It is under the hood on the driver side way back in the corner. Just need to remove the plastic gasket and cover near the cabin A/C air filter, unscrew 2 blots, and there you have it. Total time spent 5 minutes!
I ended up buying a used part on eBay. OEM Part # is: 8L0951605A. I have not received the part yet but even if the part is defective a brand new one online is about $180. I hope this helps.
Regards,
A.

 

Awesome. when I push panic or set the alarm off, the only sound m y car make is this little electronic low sounding beep beep. So maybe mine needs to be replaced?

 

I bought a used alarm born o. EBay for $80 and replaced it myself.
30 minutes, simple!

 

Mine seems to be dead, too. No $ to fix now. I could barely afford the new sig below.

-Tom

 

So what type of sound does yours make? I have had my car for 3 years but the only sound I knwo is the little tiny low beep it makes. I also saw an A8 siren for sale on ebay, may order it. Thanks for your help.