I haven't done any trouble shooting at all yet but I have 3 - 8' 4 bulb T8 fixtures in my attached garage and one of them just stopped working. From anyone's experience, is this a wiring issue, ballast issue?
I had some bulbs flicker for too long. When I replaced them I got nothing. Ballast was bad. Maybe the bulbs flickering made the ballast life shorter? New ballast and I was good to go. Only problem now is the awful soft white bulbs. Yuk!
If all lamps are inop most likely a ballast.
Make sure you have 120v between your hot and Neutral at the ballast.
Do not use a tick type as this will not confirm a good neutral connection.
Replace it with a good name brand ballast if it is bad.It will last a lot longer than a cheap one.
You probably won't want to do this, but if it were me, I would replace the 8 foot fixture with 4 100 watt CFL's. The cost would most likely be less than buying a new ballast and in the future if a CFL doesn't work, it is simple to replace it.
How old is the fixture/lamps/ballast? Don't really matter-they are all ****,they can last anywhere from one minute to who knows how many years,just change it out and hope for more life from the replacement,in these parts,GE ballasts seem to survive the best.