saturn vue 2006 alternator or........?

[Xenomorph]

It started today, my vehicle is a saturn vue 2006 3.5l fwd and all of the dash lights started flickering, my headlights flicker and cut off and my door chime will go off for a few seconds and then stop while im driving, Nothing happens to my radio though, then when it all stops for a second my power steering is gone and i have the dash light of a car with a wrench on to the left and sometimes the battery light to the right will flicker, my lights come back if i turn them off of auto and switch to high beams or on, yet still flicker. I ran tests at the nearest auto parts store and the battery, starter and alternator all came back as good, even though the alternators voltage was fluctuating during the test. What could this be?