Help alternator problems why is the check gages not working

 

computer may be seeing something the gauges are not. what ya got goin on

 

With a full charged battery the voltage my not be low enough for the check gage lite to come on.

Anytime you want a real answer you should post the cars info. There is a big difference between the gages pre body control module and post.

 

Swapped engine from junk yard, got it running but forgot to plug in old alternator, which is fairly new had no gage light, so plug in alt and its not charging and doesn't sound great etheir maybe bad ground or alt is junk all of a sudden

 

Alternator is pretty much toased from plugging it in.