low voltage

[SchmigShady]

My 92 ranger has been reading a low voltage ever since i did the replaced the 4.0 it seems to be charging i been driving it and hasn't died yet. but the gauge is only about a 1/4 of the way from the low and before the swap it read about half. its the same alt how can i check this with a meter i have one an old anlog one but it should work but i reall don't know how to use it. thanks

 

[AaronC47]

Alt Output

Go to a place like your local AutoZone and ask them to check your alt, the tester they use will show the output from the alt,