On your alternator there are three wires: The heavy " hot " wire that should have battery voltage on it; The blue ground wire that is on the alternator's long thru bolt and the small gauge wire that pushes onto a spade terminal. This is the exciter conection for the unit. When you turn you key to the " on " position there should be battery voltage at the spade terminal. Without it the alternator will not charge. Also, MAKE SURE THE BATTERY IS FULLY CHARGED AND IN GOOD ORDER. Check it with a hydrometer. Good luck.