Battery Charge warning light sometimes comes on...

Ian R formulated the question :

It can be caused by some resistance on the warning light connections. Often this will be where it connects to the alternator via a plug were salt from the road can cause some corrosion. Just try unplugging and plugging it back in (or loosening and tightening the terminal screws).

"Ian R" wrote in news: snipped-for-privacy@bt.com:

It might be something as simple as the battery getting old.

Some jap cars use a charge relay, it may be that it is starting to fail/dirty contacts.

The warning light coming on doesn't necessarily mean there is a charging fault - it could be a warning light circuit fault. If you've got a DVM wire it up so you can check the voltage while driving - using a cigarette lighter plug is one easy way. And see if the alternator is actually not charging when the light comes on - you'll see a voltage drop of about 1-2 volts. If this is happening the likely cause is the regulator. These can often be changed - although built into the alternator. It can be a DIY task but may be tricky to source one - a garage is unlikely to do this but will just fit an exchange unit. Which if not expensive is probably a better option.

I had an intermittant fault like this. Went on for months. Eventually I got stranded with a flat battery. It was the alternator.

Al.