1991 Aerostar. Alternator or regulator over charging issue?

[doonbugg]

My question is about a 1991 Aerostar with a 3.0. Does this have an external regulator or internal on the alternator ? It is overcharging at 18 volts... Thanks

 

[doonbugg]

OK, I found the answer... Internal... Thanks all

 

[BrooklynBay]

All of them are internal. You should remove the alternator, and have an auto parts store check it for you. Maybe there's an internal short in the alternator or regulator. Is the battery light on?