Alternator warning light?

[MapBoy]

Right folks My alty died last year and I got it refurbed and reinstalled it. It works fine. charges@15v batt holds@ 12ish v.
The warning light on the dash is staying on very faintly, hardly see it during the day but noticable at night.
I've just been out to check all the wires connecting to the alty and tightend them all up and the lights still on. One was quite loose, the smallest one, low down beside the oil filter.

I haven't driven anywhere, since working on it now. I just started it and saw it was still on.

Any ideas?

[Carta]

Take it for a blast and see if it goes. If not then doesnt sound good for the alternator

[MapBoy]

Wont be able to drive it till the morra. Its been on for ages with no ill effect. I just want to get to the bottom of it.

Edit: job turned out to be cancelled tonight so got to drive the car home. Light stayed on...hmmm...stupid thing!

[JDM Boy]

15v is too high,it should be more in the region of 13.8 - 14.4v
Did you measure it at idle or with the revs up and accessories switched on?

[monsterer]

15v is too high,it should be more in the region of 13.8 - 14.4v
Did you measure it at idle or with the revs up and accessories switched on?

Is there an alternator voltage regulator on the 180? If so, this could be causing your light - sorry i can't be more help... :)