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Q: Battery light is on on 2005 Toyota Highlander

I just replaced the battery today. The alternator was replaced March 1, 2011. I figured the battery was bad so I replaced the battery. Now the battery light is on and won't go off. Also today it wouldn't stay idle it just kept cutting out. I'm out of Ideas, The fuel filter is in the gas take so I can't replace it. Why is the battery light on and why is it stalling, what can I attempt to fix these issues?
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If the battery light is on the battery is not charging. The fuel injection, ignition and all the electrics on your car require a threshold voltage about 9.5 volts or the systems don't operate well. It could be a bad or unsecured battery ground cable between the battery and chassis or chassis and engine. Turn on the ignition switch to the on but not run position do you see an icon on the instrument panel representing a battery, if you do not see this battery icon the alternator is not seeing power to allow it to charge. Start the engine does the battery icon go out. Put a volt meter across the battery terminals with the engine off, at rest the battery voltage should be 12.6 volts if the battery is fully charged. Now get a friend to start the car while you watch the voltmeter, the voltage reading across the battery should read approximately 14.6 volts if the alternator is charging correctly.
At the back of the alternator the large wire goes straight back to the battery it should have power all the time, at least one other wire with the plug disconnected at the back of the alternator should have power with the ignition key switched on. There is a large fuse link in the engine compartment the says ALT it protects the alternator check it is OK. Another thought, there are a lot of rebuilt alternators that are bad quality, with the engine running hit the alternator and see if it then turns out the light (if so alternator is bad.
Autozone have some popular workshop manuals for free on line once you register (for free) on their website There is also a company that independent auto repair shops buy their information from that the same information inexpensively to do it yourselfers. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... Alldata is very easy to navigate
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