I noticed when I was driving yetsterday that my ebrake light kept turning on, I didnt think anything of it because i knew my fluid was low. I filled it up and it still turns on and I can see my battery light turn on faintly and hear buzzing from my cluster. I looked it up and it pointed to a bad alternator. I took my alternator off and went to Advanced to get it tested and it tested good, then I went to Autozone and got it tested there just to make sure and it also tested good. Assuming my alternator is good, what could cause these problems? I checked my grounds and they were fine and the battery terminals have no corrosion.

My bet would be that you alternator is not fielding correctly, Pretty much just check all associated connections for excessive voltage drop, and make sure your battery voltage is correct which I'm sure you already did. If that is not it I would look a little deeper into the wiring diagram. At the same time I have seen cars with loose battery cables do the same thing.

advance/autozone/ect bench tester really isnt that realiable. I have had numerous (used to work at advance many moons ago and they havent changed the bench tester) alts test good on the bench when it comes to voltage but not put enough AMPS out under load when installed on the car and put to work.

If you can, some new advance autos have a hand held unit that will put the charging system under load and work better than the crappy bench unit when its installed. however, i cant imagine finding one used is that hard/nor expensive. why not just grab one and try it? i typically would not recommend throwing parts at ANY problem, but i personally hate charging issues and getting stuck on the side of the road sucks...

i know u said u checked your grounds, but the one on the battery tray kinda blows...why not replace/redo that one while you're doing charging system maintenance

im going to try someone else's alternator, i dont have a dmm but i couldnt find anything wrong as far as loose connections.

I thought that I had a Bad alt for the longest time but it turned out to be a bad batt. My lights would dim at idle and radio would cut out occasionally and sometimes it wouldn't even start if I left the door open for more than 5 min. I checked it a few times but I guess I never put a good load on them to simulate my abuse (1600w amp and playful driving). All I can suggest is make sure it isn't the batt first because that is a lot cheaper and easier than an alternator.. it's hard to track something that you can't see. :/

i got my battery tested and tried an alternator off a working car. it didnt do anything. i notice if im driving at a constant speed it goes away some times but if i let off the accelerator it comes back

check the alternator connections. also try upgrading the grounds. what accesories are you running. any belt slippage happening?

I was trying to get around to checking the connections but its been cold and rainy. My battery is in the trunk and I bought a new ground cable and had it there for a few months now. As far as slippage it happens sometimes when I start the car and when its cold out but usually goes away after a minute of so and I am not running any accessories besides the regular stuff like radio, headlights etc.

sounds like you need to check your ground connection at battery to ground and at ground to engine block.

Problem sovled! It was the 10 amp fuse. The Engine Cont fuse in the engine bay