vauxhall remote central locking key

[steffs]

hi,my remote central locking on my 1998 vectra is playing up,the locking motors are working when i press the remote key to lock the doors lock as they should but they then unlock straight away.All my doors are shut properly,would a dodgy battery in the remote cause the doors to unlock straight away or have you heard of this before and can tell me what bit sounds like.
Cheers steffs