getzy3

I have a 93 civic with an h22a. I bought it like this and last week it stopped charging. Put a new alt on and had it tested and its good. Still wouldnt charge. Pulled top left horizontal pin out of alt plug and the alt started charging. I assume this means the ELD is bad?? Or could it be something else?? Also the voltage on the alt goes up n down between 13.6 and down to 10 volts, not sure whats causing this. Any help is greatly appreciated.