Trailblazer headlight not working

If ONE headlight is not working, this is my test procedure. I also explain the power and ground circuits to each of the low beam bulbs. If BOTH headlights are not working check out this other video first. https://www.youtube.com/watch?v=QgPfUrkliUg If you own a Trailblazer/Envoy or any of their cousins, join me at GMTNation.com, the BEST Trailblazer forum on the internet!!!