I took my gen. to a repair shop to have a new front bearing put in. They stated the gen. was in good condition and only had to put in one brush and the bearing. When I put it back on the car, it will not show a charge on the amp gauge no matter if I move the third brush all the way down. Do I need to polorize this or should I take it back and see if they can figure this out? Just how do you polorize the system? Thanks for the help!!