I recently replaced the stock battery in my 2004 Mazda 3 after 6 years of faithful ampage. I had been driving along and the radio started blinking on and off, followed by total loss of power steering. Upon returning the car to my house, it refused to start. So I took the battery over to AutoZone and it tested DOA - replace. Got my new battery in the car and everything seems to work except for that the battery light comes sometimes after starting it up. I took the car back to Autozone and had them test the electrical system. The battery, starter and charging system all came up good. I looked at my dash and the light was off again. I get in the car this morning and it comes back on. Make a stop at the store and upon restarting, it is off for the rest of my trip to work. Then again... coming home, it came back on upon starting and stayed on. Now if my alternator is testing good..and it's a brand new battery, what else would cause the light to come on?

 

My experiences with the best Autozone batteries have been bad.
Check the grounding wires for corrosion and clean them.
Even the best batteries can be bad. I learned this from experience.

 

what you can hope for is corroded wires, autozone does not have the correct equipment to accurately test something like that, worse case is your alternator is has a bad diode, which again wouldnt come up with what autozone would have

 

any chance you momentarily crossed wires when putting in the new battery? That could fry stuff like the alternator or other controls in the car. If the alternator and battery are ok and the light is still on - sounds like a control module / wire corrosion issue.

 

Adallons - I'm wondering what you came up with as a solution to this since it was a few weeks ago.... I currently have a dead '04 mazda 3 in my carport after the same driveway entry tonight. The battery light came on last Friday, but shut off after 20 minute of driving once the car was "warmed up". And I've only made 3-4 short trips w/it since.

Wondering if I can just plan a battery replacement, or if I need to prep myself for a pricey alternator repair! Thanks!!

 

It is most likely your alternator. I replaced my battery and the light kept coming on. So I bought a used alternator and had a friend install it. Apparently, I had removed the skid plate from under the car a few years ago, allowing water and salt to get up under the engine..the alternator was rusting, causing it to fail.