Battery Light keeps coming on

The other day my Tacoma power goes completely out while driving. I was able to get it home and first thought it was the battery. So I took it to get it checked, but the battery was good. Then I took off the alternator and that also came out good. Seeing that my battery was 2 and a half years old, I decided to get a new. Installed it and the truck fired right up, drove it around some and ran great, but after a few minutes of driving the battery light flashes on. I don't want it to die on me again and I am wondering why the light keeps coming on for me.

 

Any corrosion on your battery cables?

 

Sounds like an alternator problem. If you have a voltmeter check idle voltage them hold steady 2500rpm check again. Should be 13.8-14.2 volts @ 2500rpm

 

Same thing happened to me on my 4runner awhile back. Your alternator is on the way out. Checking it may not identify the problem because it is intermittent. It will eventually go out. I picked one up at autozone and on my way home it went out. Lucky for me it went out right next door to an auto repair facility.

 

Agree with the others about the alternator. Your brushes are worn out. You can take apart the alternator and install a new brush holder for about 15 bucks or you can get a replacement alternator.

 

Could be the main connection to your alternator too... had that happen to me once... went to replace the entire alternator only to find out the reason it wasn't working right is because it was loose.

 

Thank you all for responding it is very helpful and today I am going to switch out the old alternator with a new one. I will post my results later. Thank you again.

 

The "battery" light doesn't tell you that your battery has a problem. It tells you your voltage is low. You want to start with a $5 multimeter, not a $100 battery and a $100 alternator.

 

Yes start with the meter could be a week ground. But I have seen alot of alternatives bench test good but was actually bad.

 

Or...

Do yourself a favor before you buy needless stuff... Check ALL your connections.

 

Sorry wrong posting

 

Alright, my problem was indeed the alternator. I've been driving it around all day to be sure, no battery light to be seen.