battery not charging warning light on fiesta diesel

[traclenin]

Hi my warning light telling me the battery is not charging stays on all the time,I have changed the battery and the alternator checked the drive belt but the light remains on.Despite this the car continues to run and charge the battery so I can even run with the lights on.I have even put a new earth connection from the engine to the car body but this had no effect.I have pulled the fuses out one at a time to try and identify any circuit running to earth but this hasnt helped either .I would appreciate any ideas

[tigga]

The alternator usually has a spade connection to a small wire, this is solely for the warning light. it simply provides power whenever the alternator is working, but if it stops providing power it causes the light to come on - so its possible there may be a faulty connection on this or a break in the wire, this would explain why the actual charging system is unnaffected.

[Catso]

tigga is right, but strictly speaking, if the light is on, the alternator wouldn't be working.

FWIW, my wife had just the same thing happen, on a Fiesta diesel. The light stayed on, but the car seemed to carry on OK. Detailed investigations revealed that two of the six diodes in the alternator had failed. So in fact, the alternator was charging, but not to its full capacity.

If you have checked the continuity of the wire from the warning bulb to the alternator, and it's OK, then based on our experience, I'd advise you start looking for a replacement alternator on ebay. It will die completely, shortly.

[tigga]

Aiye just as i said catso - 'if its stops providing power, the light comes on'. However - a good way to test the continuity of the cable (the little one for the warning light) would be to connect it directly to the + side of your battery - if the light then goes out, you can eliminate any problem in that circuit.

[traclenin]

Thanks for your help,I checked out single wire from the alternator I got continuity in the cable but no power from the alternator to the cable.Its still running but I can only assume that the replacement alternator I got from the scrapyard was faulty.Thanks again for your help