Suddenly today the siren is not beeping when armed (fob or keypad) or disarmed. There were no warning signs that this was about to happen (e.g. flat battery beeping sounds). It's definitely not working as I did my impression of a burglar entering when 'arm' had been pressed. Could today's heavy rain have anything to do with this? Any troubleshooting tips. The book recommends removing the siren cover to see if it reacts but I'm certain it's not the batteries (replaced a few months ago). Any advice welcome. I can't re-learn anything because ther'es no communication fobs to siren.