SOUNDS LIKE THE ALT IS DOING WHAT IT IS SUPPOSSED TO ON THESES VEH, THEY DO OPERATE DIFF THAN WHAT WE ARE GENERALLY USED TO , ONE WAY TO GET A PRETTY GOOD IDEA IS TURN ON THE HEADLITE ENG OFF WITH A VOLTMETER HOOKED TO THE BATT, LEAVE THE HD LITES ON FOR A COUPLE OF MINUTES TO PUT A DRAIN ON THE BATT, NOW START THE ENG AND WATCH THE V/M IT SHOULD GO PRETTY QUICK TO OVER 14 VOLTS OR AT LEAST 13.5 AND KEEP CLIMBING TO AROUND 14.2 AFTER IT SETTLES DOWN NOW TURN ON THE A.C WITH ALL THE LITES ON FOR A FULL ELECTRICAL LOAD ,IF THE ALT KEEPS THE BATT VOLT TO AT LEAST 13.8 AT JUST ABOVE IDEL SPD YOU DON,T HAVE AN ALT PROB, ,YOU COULD ALLSO WIRE IN AN AMMETER AN D ACTUALLY CHECK THE CHARGING CURRENT TO SEE WHAT THE ALT IS REALLY PUTTING OUT AS FAR AS THE FULL CURRENT CAPABILITY BUT IT GETS A LITTLE MORE INVOLVED , IF YOU HAVE A LARGE FULLY (HOT )CHARGED BATT THE ALT MAY ALLSO NOT THROW A FULL 14 VOLT OR SO UNTILL THE BATT IS DRAWN DOWN A LITTLE BIT .JERRY