The battery dies in my 2007 GS350, but the is no charging system fault message on the info display. I can charge the battery, and every thing works fine until the battery runs down and I get the the red battery warning lamp on the instrument cluster. Clearly no output from the alternator to the battery, but the lack of a charging system warning is curious. Is it possible that the alternator is working but the connection to the battery has been disrupted? I hit a mean pothole shortly before this problem arose. Is there a connector that could have been jarred loose or a fuse damaged or some such thing? Is there a terminal where I could test for output directly at the alternator?

Thanks in advance for all replies.
Jon

 

You need a voltmeter put it on volts 20 volt range and test the battery before starting it, test again with the car running. You should be at 13.4 volts and up at the battery terminals. If you are not getting that voltage then you can test the voltage at the alternator, theres a big power wire you want to put black on any chassis steel, and red positive on the power wire coming off the alternator. If you are not getting power out of the alternator then its time for a new alternator. I would only buy oem reman or denso reman, I would avoid cheap chinese alternators.