Last night the battery warning light came on when i turned on the ignition and got brighter as i revved the engine. It won't disappear at all now. It's dim when the engine is idling and is constantly on when i'm driving. I've checked the voltages both when the engine is on & off and its around 13.5V-14V.

The battery and alternator are both only a couple of months old and the drive belt is still fairly good condition. Any ideas of the problem?? could it be a faulty alternator?

possible regulator fault or warning lamp wire shorting out

The regulator came with the alternator so its brand new as well. Is it worth buying a new regulator and checking if it resolves the problem? I changed the belt today to see if the situation would improve but no luck. May have to be a garage job if i can't figure it out soon

New alternators have been known to fail with these sorts of symptoms too. It happened to my dad once.

tried a new regulator in the alternator but it hasnt made any difference. I've noticed that the alternator is not straight as well. Looks like it will have to go back to the shop

hi I had the same fault with my felicia. The AA tested my battery and alternator ,I ended up buying a new battery and alternator..

I need to send my alternator away for repair and there is something from my old alternator that I had to attach to it and I want to make sure I get it back. Can anybody tell me what it is? I think it's some sort of capacitor or something. (The small white box thing at the top of the pic). Is it also possible to buy a new one or necessary to buy one. thanks in advance

The markings that I can read on the box are mildly confusing; one seems to be a marking in microfarads, which would be a capacitor rating, but the other shows a circuit diagram of a capacitor in parallel with a diode.

I've spoken to an electrical engineer and he reckons its to stop back emf on the alternator so that it doesn't damage the insulation. I take it not much can go wrong with these in terms of the operation of the alternator so I don't think I will need to buy another one. thanks for the replies

when i broke down half way down the m5 it was that little bit of plastic on the side which had blown up - literally melted and was smoking, i havnt got a clue what it is, i always thought it was the voltage regulator