I put a new (ebay) alternator on my 99 C5 and drove a few blocks, got a "CHARGE SYSTEM FAULT" Put the old alt back on, no problems. The battery is strong. The electric system has never had a problem. My old alt works fine, I just wanted to get new bearings for racing, that's why I bought this new one. Any ideas??? Is it a compatability problem. The Ebay alternator was for 97-03, maybe there are different years that are not the same electronics?

 

We've had a ton of problems with aftermarket or rebuilt altinators. We only use GM one's now.