Alternator not charging

I have a 2007 4.7 Tundra. The battery light pretty much stays on all the time. I checked voltage at the battery while truck was running, and it was only 11.5 volts. I charged the battery, no change, I pulled the alternator and had it bench tested, and it passed. Any ideas? Thanks

 

Given the age of your truck (and I'm going to speculate 125,000 miles) I would replace the brushes inside the alternator. Not the alternator itself. The $15 brushes that are the wearing component on the inside of the alternator.

Here's the brushes from my 1997 Toyota T100 trucks.

 

231000 miles. I had the alternator put on the bench and tested and it passed?

 

How is the volt supply directly on the alternator ?

 

Seems to me you have a battery with a dead cell

 

12.7v when battery was charged. It about 7 miles, power dropped to 12v.

I will pull battery and have it tested.

 

You'll want to dig up a wiring diagram for your specific truck and see how the field winding is energized. It was definitely a good idea to have the alternator tested and the battery tested before just throwing them away. The fault you have probably won't be expensive to repair but it will take some time to find!

 

I would check the alternator fuses. There is one for the output ALT (140-180 amps) and like a 7.5 amp fuse (maybe labeled LH-IG) and 5A ALT-S fuse (probably for the indicator but check it anyway).

 

Is that 140-180 amp fuse a part of the "fuse block", that is under the clear plastic cover in the fuse enclosure under the hood?

 

Should be #62 for the 140 amp
#48 for the charging system. But it looks like other stuff would not work like turn signals if that one was bad.
#14 is the 5 amp ALT-S

 

Update- alternator is charging again. The only thing I did was pull the alternator out had it tested and reinstalled. I am making the assumption that the issue was due to water, and components getting too wet. We have had a lot of snow and then it was quite a bit of slush on the roads.

Thanks for eveyones help.