I went through all this replacing everything and anything with the alt/charge system,turned out to be emissions related. Dont know about 82 but my 83 has a computer and it was running way rich and the computer trips the charge/brake light combo indicating a problem like a check engine light, so if you have exhausted all other options it is something to consider. I had to find someone familiar with the old yotas and he knew right away,rebuilt carb and a few vacume items and no problems anymore.
