Two years ago my 24 inch single T12 tube magnetic ballast fixture stopped turning the bulb on unless I touch the bulb. I changed the bulb, still not working. Changed the Ballast, same thing. If I touch the bulb it pops on. If I wrap a bare wire around just a few inches of the bulb and ground this wire to the fixture it lights without having to touch the bulb. I sanded the point that the main ground wire attaches to the fixture and tightened it really well, still won't work. This only happens in summer time. When the air dries out and it cools off in the house it works fine even without the wrapped ground wire. I cannot figure this thing out??