battery light stays on but running fine

[sambo42xa]

My 2007 (99k) is pretty much doing the same thing. Only differance: car is running at idle and the battery light flutters not to the point it goes out. While running I remove either battery cable or even both and the battery light stays on and does not flutter (car is still running). Put the cable/s back on and the light flutters again.
With car off I removed the battery cable off of the alternator and cleaned the connection since it did have a little bit of corrosion. The pin plug I removed also but did not see any corrosion. Output on alternator was around 13.8 and the same at the battery. No change after cleaning connection.
From what I have read here, it seems you folks are steering more towards the alternator (internals) than the battery. No problems starting car so I'm pretty sure the battery is fine (13.8 volts). Everything else works fine. Are there any readings on the pins I can check or are we 99.9% sure it is the alternator?
I'm good with mechanics and I'll check/test whatever.
Thnx in advance!
sambo

[CTScott]

Originally Posted by sambo42xa

My 2007 (99k) is pretty much doing the same thing. Only differance: car is running at idle and the battery light flutters not to the point it goes out. While running I remove either battery cable or even both and the battery light stays on and does not flutter (car is still running). Put the cable/s back on and the light flutters again.
With car off I removed the battery cable off of the alternator and cleaned the connection since it did have a little bit of corrosion. The pin plug I removed also but did not see any corrosion. Output on alternator was around 13.8 and the same at the battery. No change after cleaning connection.
From what I have read here, it seems you folks are steering more towards the alternator (internals) than the battery. No problems starting car so I'm pretty sure the battery is fine (13.8 volts). Everything else works fine. Are there any readings on the pins I can check or are we 99.9% sure it is the alternator?
I'm good with mechanics and I'll check/test whatever.
Thnx in advance!
sambo

The blue wire on the multi pin connector on the alternator is the output to the cluster that drives the indicator. The service manual says that the normal operating range is 11 to 14 volts, so you could measure the voltage on that wire to see if it is fluctuating. The pink wire is a signal to the ECM and AC ECU. Based on the output of this signal, the ECM can tell the cluster to also light the indicator.

There is a TSB for 07 Yaris about a potential internal corrosion issue of the voltage regulator, which can cause the behavior that your are seeing, without actual charging issues.

[sambo42xa]

CTScott- I was just informed this evening from my wife that the Battery Light went out. Though she didn't notice if it was out when she started the car or if it went out while driving.....either way I will take reading/s off of these pins tomorrow and see what I come up with so I know for myself what to look for next time. And this willl help for Others on the forum which is what it's all about, right?
.......too be continued...........
thnx, sambo
southern, nh
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