alternator wiring??

[Brenner5]

from what i can see the alternator has 2 wires coming from it,

one is a large one which goes to the battery and the other is a small one which probably goes to the ignition system??

i have been told that there should be three wires on the alternator??

i have a 325i on a H plate

[Brianmoooore]

You've been told wrong.
A large red wire to the battery, via the starter motor, and a thin blue wire that goes to the ignition light. It also puts in an appearance in the diagnostic socket.

[PeteE30Tourer]

Moving this to the Technical Section.