I have a 1990 Honda Prelude Si. Alt and battery are both tested good and battery still doesnt stay charged. The next thing to try is finding out if the charging light has anything to do with this. I have the wiring diagram for the alternator and there is a wire that runs on both sides of the light. The charge light has not come on since I bought the car. If that light isnt coming on could that be the reason why my computer isnt connecting to the alternator to tell it to charge? Please helP! I bought this car in may and have been dealing with this issue since I bought it. The guy I bought it from said that i Just needed a new alternator so we got that and still nothing is working the way it should. Im ready to give up on it!