[A4] central locking dodgey

[Jonathan]

Hi All,

Been a bit quiet on the list lately...

I have a 96 A4, and sometimes the central locking just doesn't work. I've 
found that with the alarm, it always locks. However sometimes I need to turn 
the alarm off then on (using the key fob) several times to get the doors to 
actually unlock. If i give up and use a key, it only works on that door. 
Also, If I lock the doors from the inside, sometimes it only works on that 
door, and takes a few goes to get all doors to lock.

Any Ideas?

I've heard of people having issues with alarms caused by a dieing battery. 
Does that sound right? if so , how does one replace a battery?

cheers

Jon