Originally posted by Big Jim:
First of all get the battery charged and tested. A completely dead battery can keep the alternator from charging. If the battery tests bad after charging, replace it, then test the alternator. You may only need a new battery.

Once the battery is qualified, you need a voltmeter to test the alternator. With the eingine running at about 2000 RPM (that would be gently reved up) and all electrical accessories off, you should have a voltage reading of about 14.5 volts. It may be a bit lower if the battery is not fully charged (a new battery may not be fully charged).

If the alternator isn't working you will have nearly the same voltage as with the engine off (about 12.5 volts).

Bdfore condeming the alternator if the voltage reading is low, check the mega fuse in line between the battery and the alternator. Also check the belt to make sure the tensioner is holding tension so it isn't slipping.

I hope this helps.



Took the battery to Autozone to have it tested this morning. It was completely drained and failed the test when it was charged back up.

Luckily it was under warranty, and they gave me a new one. Unfortunately, that didnt solve the problem. I was able to start my car, but the battery light started flickering again upon revving the engine.

I luckily own a multimeter- so I measure the voltage on the battery with the car off. Roughly 12.5v. With the car started it measured a little less than that...

So I went back to Autozone, and mention the possibility of the Megafuse and the guy kinda just scoffs at me and tells me its definately the alternator "If a fuse went, you wouldn't be getting anything at all." I don't know what that means...

So I call around all the local mechanics and the best price I could come up with to replace the Alternator was $242 from Pep Boys. And it won't be a brand new alternator, but a Factory Re-built one.

What do you guys think? Does the guy from Autozone know what the hell he's talking about?

And how can I check the Mega Fuse? I understand that it's inline between the battery cable and the alternator, but where? I can only follow the cable so far... unless I have to get at it from underneath the car.

Thanks again for all the help. I feel like I'm learning a lot here too.

-ant