battery light

[redmatt]

What do i check first, I'm driving along and the battery light comes on it then stays on whilst i do 25 miles or so. i get home take the keys out of the ignition and the light stays on, the next day the battery is flat. What a pain. Don't really know what to look at first.

[Nacnud]

Giz a clue - what sort of Wedge are U in ?
Your profile doesn't seem to say.

[Nacnud]

Seriously, there are big veriations in electrics. I've got abot 40 fuses in mine!

I've had the battery/alternator light come on twice.

One time was a short in one of the side repeaters which blew a fuse causing the alternator light to come on and also turning on the driving lamps!

The other time was throwing the alternator belt by over-revving for the crowds at Le Mans

Never heard anthing like a light staying on after the key is out though - sorry.

[AM400]

Nacnud said:

Never heard anthing like a light staying on after the key is out though - sorry.

I have, its happened to me twice! both times it was the alternator.Get it tested first though to be sure!

Andy.

[danny hoffman]

I agree it's prob the alternator.

[streaky]

Humm! If the battery is light it probably needs water and acid (and maybe lead) adding.

Sorry, couldn't resist it!

Streaky

[terence]

I have had this happen in the past, both times the cause was a failed rectifier diode in the alternator. Unless you fancy stripping the alternator and replacing the diode pack (will need soldering iron) best roue is probably a service exchange.

[jonres]

Yep, me too - I had the same problem, and it was a dead alternator.

[father ted]

....exactly same happened to 3.5 V8 range rover i had....diode rectifier pack blown.....if it happens the battery drains back through the alternator....battery light will illuminate,keys in or out and ,hey presto,flat battery!
Not expensive if you 'service exchange' somewhere.

[mrcrappy]

is the alternator giving anything out if not it may just be the exciter wires come off

[redmatt]

got to test the alternator by the sounds of it i have another one but should check it first i suppose thanks to you all its seems conclusive if you can ever say that of the electrisc on a 350i (thats the car) and i like the joke by the way ill let you know.