I have a 93/94 wrx and the alternator went a few months back but I was lucky as I found one in a scrap yard that looked almost brand new any way I fitted it with no problems and it sorted the problem out
But this morning on my way to work the batterie light on the dash came on at tick over at first when I rev the engine it went out and flickered back on at tick over
Now after just a few miles it comes back on and stays on no matter what the revs
At first I thought it was the alternator again but I have rigged up a multimeter to the cig lighter to see if the voltage goes down when the light comes on but no when the light is off the voltage is at around 13.5 volts and when it comes on its around 13.9 volts
Has any one any ideas as to what it might be ?

Well it's a light to show that the alternator is charging the battery. When it comes on, it's not, if you see what I mean?

I'd take it to a reputable car electrics place and have the alternator charging circuit tested.

If it's NOT charging, expect your battery to die sooner rather than later in this weather:(

Alcazar

Would it not indicate over charging
Its defiantly charging the batterie when you stop the engine the voltage drops down slowly and settles at about 13 volts or just under

Would it not indicate over charging
Its defiantly charging the batterie when you stop the engine the voltage drops down slowly and settles at about 13 volts or just under

Unlikely to indicate OVER charging, unless it's wired differently to most cars.

But even if it was, it's worth getting the alt checked as if it is OVER charging it'll soon kill your battery by boiling it dry:eek:

Alcazar

Up date on the light
Later on on Friday my dash lights started to get brighter and when I connected my volt meter it was charging at 17 volts so iv taken my alternator to my local auto electrician to have it fixed I should get it back today some time

sounds like a regulator to me make

Just had a phone call from the chap meant to be fixing my alternator but unfortunately he carnt fix it
He says the reg has gone and the diodes and he says he carnt get the diodes so now im stuffed a bit
One place wants £85 + vat to recon my old unit

sounds about right mate bro thought it was the reg, it stops it from overcharging above 15.2 volts as an alt will charge at anything