alternater problems

[holden lover]

hello.long time reader, first time poster.........
iv had my vn commodore for over a year now and have done a few mods here and there. a week after i got it, the battery light came on. my first thought was brushes, but to my surprise the light went out so did nothing. long story short, the light will stay on untill the temp guage goes over the 2 line and the thermal fans kick in, and it goes off(the light).
iv done tests with a multi meter and when the light is on, and engine idle it reads 10-11.5 volts. when i increase revs it goes to 14volts but the light remains on....
any ideas would b greatly accepted because driving at night and in the rain it a major hassel with dim lights and slow wipers.

its a series 1 motor with a auto behind it. the alternater has never had anything done to it. the car has only done 170000 ks

[bcw61]

At that amount of kms, I would still suspect the alternator brushes. As they start to initially wear enough to start losing contact with the slip rings, they may cause the alternator/battery warning light to come on only intermittently, until they continue to wear enough to lose contact with the slip rings more permanently. Brushes can be replaced cheaply, if you're handy with a soldering iron.

I had a similar thing happen with my old VN series 1 V6.