seeing you've been running the truck for awhile, it's not likely to be your problem if you haven't killed the battery yet, but to polarize the generator [key off], touch a piece of wire momentarily between the Batt and Arm terminals on the regulator - it won't hurt anything to try
might also check all connections in the generator/regulator and battery circuit - and it could be a sticky regulator, try a sharp rap with a screwdriver handle while engine running [really
]
Bill
