Your alarm ( if its the factory fitted one ) has nothing to do with the code system so it should start anyway although siren will still go off.
Your code light should come on with ignition and go off a few seconds later.
you were right. Bought brand new battery for £113 form Halfords then put it in.OK.
key in ignition and turn then alarm went off. Car did start.
Drove off, locked the doors from inside and after few meters driving the alarm gone silent on its own.
But when the door was opened again alarm went off again. Sheesh.
Took to Arnold Clark, no help, as they said they are no more alfa romeo dealers and wont be able to help, Went to taylors Electrical , they also of no help as they said they didnt have diagnostic equipment for alfa 156. The nearest dealer for alfa is in Perth. What a joy owing an Alfa!
Finally have taken it to last resort in Aberdeen Kirkhill auto electrical. The guy seemed helpful and said he will do something and let me know tomorrow morning.
Why cant we just take these alarm components out of the car system, why not? Such a pain I tell ya. And moreover UK Alfa's dont have alarm emergency turn off key. WHy WHy?
Hope it solves with less expense.