Alternator or battery?

[RobW]

Pretty sure its the alternator, just need confirmation...

Battery light on the dash, battery at 12.2v with engine off and at 11.4v with engine running.

[barney490]

Sounds like alternator to me,you should have 14.4v at the battery with the engine running.

[david.aka.judas]

can you borrow a battery of someone and test to see if it's different????

[Das]

Sounds like alternator to me,you should have 14.4v at the battery with the engine running.

[tony-1977]

Agree.... Alternator dying.

[zafira]

Sound like the alternator. It been a problem on some vectra. Thise dont like engine-wash was told me by an opel - mecanic.

[LJ sxi-nav]

same problem on mine, although had no battery light warning of a charging fault - just wouldn't start after stopping for fuel!
sourced a refurb'd alternator from ebay for £110 and fitted relatively easily following the how-2 on here, and the haynes manaul. Vauxhall quoted me £200+ just for the alternator and close to £350 Supply+Fit!!
(I have a 120bhp CDTI - 105A alternator)

[RobW]

I bought an alternator a few months ago when the water pump went so just need to get it changed.

Just got it back from a new manifold too.