simple circuit , power to reg & field blue wire , green wire grounding field to reg which controls the ground to limit charging , if the reg & alt are OK then you have a number of issues , connations at both bulkhead plug , ammeter , or bad ammeter gauge , or the alt cannot put out enough power to supply everything so you may need a higher output alt , if you do go higher than 60 amps I recommend a bypass from the alt directly to the bat connection on the start relay on the left inner fender ,