Thread: Battery warning light, but charging

generally a low battery in the plip will cause the immo light to be on solid, turn off then on and its gone is the characteristics.

No resolution yet, but a bit of an update.

The red battery light is coming on every drive now, and also have a rattle up front off the sertpentine belt. The alternator pulley appears to lock and free-wheel as required, but maybe it's a problem? I replaced the tensioner bearing, but others were OK. It made no difference to the rattle. A/C on and off and the rattle doesn't change.

So I took it to an auto leccie yesterday and, of course, the fault light didn't come on. He can't fault the alternator, nor it's pulley. He thinks the rattle, which he heard when I drove it in, might be the fan. The bearing's good, but possibly the hub? He thinks the electrical fault might be in the wiring loom, but nothing positive after 2 days there.

Well the red light only came on for a few seconds for the leccie, so I'll have to take it back when/if it becomes more regular again.

He has ruled out earth issues and the wiring loom. Perhaps the fairly new alternator has a fault? Or the ECU has a glitch? Very decent bloke...he didn't charge as he didn't find an issue.

He identified the rattle using a stethoscope...it is the tensioner, which I had out and replaced the bearing in it. The spring was strong as ever. Nothing appeared loose inside and it had a new bearing, so what fails in them?

It's got 375,000km on it now so I guess weird stuff happens! Any more thoughts welcomed & appreciated, of course.

I replaced the tensioner assembly, but it also rattles!! Observing it at cold idle, when it's most evident, the rattle appears to coincide with more movement/twitching of the tensioner arm against its spring. It's a regular rattle/twitch. cycle every few seconds

I'm wondering if this is in response to a fluctuating load on the serpentine belt. The battery light was ON at this stage, but charging at 14.2V. Maybe varying current draw from the alternator? All pulley bearings are new or near new and feel good. The Alternator clutch seems to lock up and free wheel OK.

The voltage stayed at 14.0V at idle with high beam, both spotties and fan on fast speed, but I might retest with a rattle at cold tomorrow. Any other suggestions?