Battery light flickers upon startup.

I am new to this forum. I have a 2006 Tacoma 4x4. I am currently living in Mexico. Upon startup most days, my battery light flickers and then turns off within a couple minutes while driving. It does not come on while driving after the warmup. If I wait a day and start it up it comes on again. I thought it might be a worn serpentine belt but I just had it replaced and it is still happening. I am really not in a great location to replace the alternator but I would like some input as to how to test it to make sure the alternator is good.

 

Sounds like the alternator may be on it's way out, put a meter on it and make sure it's charging. If it is it may go awhile yet, if it's not do the checks in the post below.

https://www.tacomaworld.com/threads/2nd-gen-information-diagnostics.784008/#post-28042155

 

Yeah thats your alternator going out. It wouldn't hurt to check the electrical connector on the alternator is secure, remove and and click it back in place. A month or two ago my running voltage dropped down to 11-12 volts right after startup with no accessories on then went back to normal 13v after a min or two, but 3 or 4 days later the battery light was on when I started it and the alternator wasn't putting out anything.
The 4.0 alternator isn't to bad, took me about 2 hours to get my swapped out, first time changing the alternator on a Toyota but I am a professional mechanic so I do have general experience. I do remember taking it out the top of the engine bay and having to bend the hard ac line about a inch or so to get squeeze it out.

 

An alternator not charging a battery that is getting on in years means the battery might be injured by this. A portable battery boost like a NOCO GB40 might be good to have in case the battery was hurt.

 

As others have said, the alternator is likely on its way out. The battery light in the Tacoma is one of the few out there on cars that actually tells you exactly what the problem really is. For the majority of others it could be anything: belt gone, battery on it's way out, low charge at idle. In a Tacoma at least, it's always an indication/telling you the alternator is on it's way out. I have had cars with an "Alt" lamp that never came on even when the car died from a dead battery and left me stranded.