2003 Sienna - intermittent battery light while driving

Hi:



I have an '03 Sienna with 132K kms, still on it's original battery from 11/2002.



I've maintained the battery well, topped up the cells with distilled water twice a year, terminals are clean and greased, voltmeter reads 12.75v with engine off and ~14.5v when started.



Recently, wife reported that twice, while driving at 50-60km/h, the battery light on the dash came on for 1-2 minutes and then went off by itself. There haven't been any starting issues in the morning, it's parked outside in -10C to -15C temps.



Is it time for a new battery and/or alternator or it's an issue with the charging system?



Thanks in advance.

Reply 1 : 2003 Sienna - intermittent battery light while driving

I would say its time for a new battery. 8 - 9 years on a battery is as good as its going to get. Sure you can probably get by but I would rather spend my money on a new battery that pay a tow truck. Cold weather actually improves the life of a battery since the water doesn't evaporate as fast, but it starting an engine in cold weather takes more "power" than warm weather.



If I recall correctly, the battery warning light indicates that the battery is not being charged and points more to an alternator problem, not a weak battery problem.





Either way, you will need a new battery, and possibly a new alternator. First, check your alternator belt to make sure that its not ripped, dirty or greasy. Check battery terminal and ground connections. Not sure if you plan on fixing the van yourself or taking it to a repair shop. If you are good at fixing the van, then I would definitely replace the alternator. You may be on borrowed time with the alternator so (again) pay for a tow truck or fix the van.



Hope that helps.

Reply 2 : 2003 Sienna - intermittent battery light while driving

The problem isn't the battery. The light indicates that the charging system isn't charging and that voltage is dropping. The charging electronics are built into the alternator so if it's the electronics or the alternator the alternator must be replaced. I guess if you are cool enough you could rebuild it. Alternator rebuilding seems to be a dieing art.



There is also the possibility that there is a poor connection somewhere. Check the wires on the alternator. Check all of the wires that connect to the battery and possibly even the grounds.



The battery is probably near the end but you won't find out until a hot day in stop and go driving. Way down here in AZ we get a new battery almost every year.