05 Tacoma 4x4, Charge Light on but Alternator is Charging Fine

Hello,
I recently inherited an 05 Tacoma regular cab, 4x4, 2.7 off of my late father in law. The truck is a little rough, but after looking at it a little closer, its not too bad. A paint job and some basic maintenance should make it into a nice truck.

Anyway, the charge light is on. Usually, this indicates that the charging system is either not charging at all, or over charging. But, on my truck, I get 13.7-13.8 volts all day long, no matter what kind of electrical load. Its the same at idle and cruise RPM. According to my volt meter, the charging system is doing its job. So, why would the charge light be on? Any electrical gurus out there?

Thanks,
Cameron

 

Bad body ground. Strart simple when it comes to electronics.

 

Good idea. It's easy to over complicate this stuff sometimes.

 

I cleaned all of the body grounds that I could find. No change. Any ideas?