I installed a new used engine wire harness this week after engine fire caused by old alternator burning up last fall. The replacement alerternator came from same junk yard and is plug type with three wires and main positive connection on back. My old alternator was more round in the back and was hard wired if I remember correctly. The alteranator does not seem to be putting out enough or any voltage , (about 12.6) is there anything to check before replacing it with a new alternator? New batteries work good but I am afraid they are not going to last long if my charge rate is too low. I did have some mice living in the elctrical cabinet and repaired two chewed up wires by diode assembly? Anything else to check before buying a new alternator?