How to reset an EA Fairmont car alarm that was working and now doesn't seem to be.

If you disconnect the battery and then reconnect it, the alarm then activates. You can then deactivate it with the remote thats fine, but then if you leave it for any length of time unactivated after that and then try to activate it, the central locking locks the doors, but the lite on the dash remains on and continuously glows instead of flashing and the indicators dont flash at all, as they would normally if activating correctly.

If you do arm the system at any time after reconnecting the battery, and then enter via the key and turn the car on, neither the alarm or the immobilizer activates, the car will start efficiently with no problem.

The lite on the dash will only flash if you immediately arm the system after you reconnect the battery, but it does not seem to arm the system or the immobilizer.

Do I need to reset the alarm? And where is the factory alarms 'black box' situated, under the dash? I really do not want to remove the alarm, unless it is as a last resort.

Any help would be appreciated. Thank You