I just tried to start my 08 Ultra Classic and the alarm went off. Checked the key fob battery and it was low so I replaced it with a new one. It's doing the same thing, when I turn it to ignition, the alarm goes off. My other fob works fine. What gives ??

Alan

 

Check the voltage on the new battery if you have a meter.
If not try swapping batteries.

 

Could you have the battery in backwards? Double check the '+' & '-' labels. If I remember correctly, the '+' side faces into the bracket that holds the battery.