Ignition/Battery Light. Alternator?

[Flintstone]

Flat battery. Car had not been used for two weeks and although it has held up for longer than this in the past I just put it on the charger.

Next morning after starting the engine the ignition LED (dashboard) and battery warning light (on speedo) stayed on. Blipped the throttle to 3500rpm and the lights went out.

Went to buy a new voltage regulator. "It looks different" says I. "It's the same thing" says he. No it wasn't. I had neither the LED or battery warning light before or after start.

Fitted new alternator. Nice bright LED and battery warning light before start, and unfortunately the same after start. Bugger. Blipping the throttle didn't help this time.

I didn't remove the alternator, a friend did, but I fitted the new one. I'm fairly sure it's wired properly. Power to the terminal with the 13mm nut, warning light feed (spade connector) at the opposite end and the remaining lead in the middle. The leads won't easily go anywhere else.

If this is wrong how else can it be fitted?

If this is right what else could be the cause?

Edited by Flintstone on Wednesday 23 August 18:47

[Cider Andy]

Have you checked the 100A charging fuse? Not all cars have it, it's usually mounted on (or near) the chassis rail in front of the starter motor. Plenty of info about it on this forum.

[kenny chim 4]

I've dug up an old thread about the alternator wiring- here:
www.pistonheads.com/gassing/topic.asp?h=0&t=223043

But, as Andy said, I would also check the condition of the fuse. It's on the main battery to alternator link, encased in a black plastic box. 10 a penny at a good factors.

[Flintstone]

Thanks chaps, will check it in the morning.

[biggiles]

I changed my alternator a while back. I put some photos on flickr here www.flickr.com/photos/grcm/tags/alternator/ which may help you check the wiring. (you should be able to see the photos at full size if you click on a photo and then "all sizes" above it).

[Flintstone]

Got under the car and looked at the fuse, all in one piece it seemed although it was loose so tightened the nuts. That should do it (but didn't).

Got a friend who understands these things to poke a multimeter at various wires and bits, turned out there was no feed to/from the alternator

Closer inspection of the fuse showed that it had not blown but snapped, out of sight beneath one of the securing nuts.

One 10p fuse later

[PeterC]

I had charging problems for a long time which ended up wrecking two batteries. This also turned out to be a loose 100A fuse. The factory seems only to use plain washers under the nuts that hold the fuse and over time the nuts come loose probably due to heat. I believe that this is the root cause of most of the problems with this fuse.

I would recommend to everyone that you check the condition of the fuse (if fitted) and renew, adding shake-proof washers under the nuts to avoid them comimg undone.

Shake-proof washers in Peter speak are the black spring steel multi-point washers or you could try the nylon inserted lock-nuts.

[Cider Andy]

PeterC said:

I would recommend to everyone that you check the condition of the fuse (if fitted) and renew, adding shake-proof washers under the nuts to avoid them comimg undone.

Or get rid of this pointless fuse completely.