BTW: The simplest test is with a voltmeter. The battery should be at 12.7 with nothing ON. With the engine running it should read 14.1-14.4. If you get these reading the Alternator can be considered workeing properly according to the HELM. Load test devices will also give valid readings. There is always a possibility the ELD (regulator) in the underhood MAIN fuse panel is bad-but very unlikely.