ok Guys a quick one for you, I have a 1.4i cvh escort which I changed the alternator on last year and changed the battery on last month, but the battery light still comes on every now and then, when i checked the battery with the ignition off, it was 12.47 volts, with just the engine running idle it was 14.11 and then with wipers, radio, lights and indicators on it showed 13.77 volts, so I would say that the alternator and the battery are ok, so what do people think it could be? It mainly happens when im on the motorway at 75ish or if i give the car a caining, Im crap with electronics so i havent a clue from there

 

check the blue wire that comes off the alternator and goes to the bulb in the dash, if this is damaged will cause light to come on and the alt will stop charging, it may be a loose connection or damaged somewhere?

 

Thin wire from back of alternator may be earthing out somewhere or the resistor/diode pack on the alternator is on its way out and only showing up on high RPM ?

As its still charging it sounds like the thin wire problem needs looking at first

 

If the thin blue "IND" wire has a break in it, it will NOT STOP charging, but WILL prevent it starting to start with.
Once field windings are excited by live curent travelling down blue wire to alternator it will stay charging unless the engine is stopped.
It sounds like a dicky connection on the rectifier/regulator, I would wait until it goes as it could live for years like this.
tabetha

 

The wire seems ok, and like said it only really comes on when the revs are high, so Tabetha it will be ok to drive until it needs a new alternator? or is there a possibility that something else is a miss?

 

i had the exact same problem and it was the thin blue wire earthing on the exhaust under hard boost - but obviously your wire is fine you say, so its not much help

 

It's charging at the moment, so might as well get some more use out of it, it could pack up tonight it could last ten yeasr there is no way of telling.
tabetha