01 Tacoma Battery Light

I have an 01 Tacoma 2.7L 4WD Automatic Regular cab. I got in my truck to leave the other day, and my battery light was on. I figured it was my alternator or battery so I took them to get tested. The alternator tested bad, but the battery was solid. I threw the new alternator in and fired her up, but the light was still on. I figured it must be bad connections, checked the terminals, ground to the block, ground to body, positive cables, 120A fuse, ALT-S fuse every thing seems to check out. I'm lost any ideas?

 

With the engine running, what voltage are you measuring across the battery terminals? How much does it drop when you turn your lights on high beam and other electrical accessories on?

 

I haven't checked I don't have an meter to check it yet.