vauxhall vectra 19 cdti 04

[gossie8]

then start up all ok but within 5 mins the red light comes on,the car drives ok and does what it maked too do,the only thing it does is the revs pickup and gos back too normal right away,at night when the lights are on they go very blight and go back too normal right away.i am putting a new alternator on this weekend,i was wondering what i have too look out for as well.hope someone can help me out thankyou

 

[Burnerman]

The voltage regulator is goosed in your alternator mate - but thankfully the new alternator comes complete with one.....everything should be sorted.
John