Alternator?

[jonbarrett]

Just broke down at a rather busy roundabout: battery flat due to failed charging. AA bloke was top chap, swapped battery, and got me home.

At night, with the lights off, I can just see the alternator light slighlty glowing. Is the brightness of the alternator light proportional to the voltage drop?

I assumed the alternator light would be on or off according to whether the battery was charging or draining?

[Nicholas Blair]

Could be your 100amp fuse has gone. Did you notice erratic/or no movement in the rev counter or speedo per chance?

Bugger to fix if you're all fingers and thumbs.

[jonbarrett]

Yep rev counter dropping to 0 then rising again.

[optimax sniffer]

when mine had an erratic rev counter and speedo, it was the diode pack on the back of the alternator that was failing. Go for the big fuse first though.

[kojak]

I've had my alternator, battery and starter done ans my alternator lite is still slightly visible when its dark.

Just to add. When I had problems, the lights on the dash (alternator and oil pressure) had been wired up wrong way round, which according to Joo, is not that rare. In the end, what I thought to be the alternator was in fact, the oil pressure switch, or something like that. £10 for a new one. In the mean time, i'd spent money on a new alternator/ belt etc....

Edited by kojak on Sunday 25th January 13:39

[Ballsy]

You can check the voltage of the altinator, with the car off you should get around 12v and with the car going it should go upto about 13v.
Altho if your rev counter was going erratic then a quick check and change(there cheap as chips anyway) of the 100a fuse might cure it.

[volospian]

I'd just like to say that my alternator produces virtually no charge at idle (cold idle seems to settle around 800rpm, warm idle more like 900) but needs to get up to around the 1k rpm mark before it produces any real charge, so if you're checking charge, make sure you give it a little revs, just to make sure...

[optimax sniffer]

volospian said:

I'd just like to say that my alternator produces virtually no charge at idle

AFAIK ajp's don't charge at idle. Which is why at night time, sat in traffic, in the rain is not good.

[volospian]

optimax sniffer said:

AFAIK ajp's don't charge at idle. Which is why at night time, sat in traffic, in the rain is not good.

lol, and forget listening to the traffic report on the stereo to see why you are stationary

[optimax sniffer]

Just to add...

when is there a good time to be sat in traffic?