Does the car have an alarm, if so is it original Vauxhall or after market?
Generally :-
open bonnet
slacken, but dont remove, negative cable on battery
turn ignition on but DONT start car
turn ignition off and remove key
you now have about 15 seconds to lift negative cable off battery - any slower and alarm will sound as it thinks car is being tampered with.
Make sure cable does not fall back on to battery terminal, tie it up.
Remove battery positive cable.
Undo clamp which holds battery in place.
The bolt on the clamp will probably snap unless it's been removed recently.
If it does you'll have to drill and re-tap it.
Make sure you have the radio code (if required)
After refitting battery you may have to re-sync the remote locking (if fitted).
77dan77
August 2009