Matt thanks for the help, and in the future I might need what you said here. Actually I just got my rig running right today and here's how. After taking the alternator to O'Reilleys and having it check out "good", I put it back in the rig and still had the problem. So I tried something, I started the car then pulled a battery cable, the car shut off. If the alternator had been good, the car should've kept running on alternator power alone, but it didn't. So I took the alternator out again, ordered a new voltage regulator off Ebay for $25, opened up the alternator, replaced the regulator - no more problem!