Lighting, Light Fixtures, Ceiling and Exhaust Fans - Fluorescent Lights

I have a 2-bulb florescent light fixture with a motion sensor light switch that has worked fine for the past 10 years. This time I replaced both bulbs but one comes on really dim and the other doesnt come on at all. The motion switch has no ground, It only has 2 wires coming from it. I suspected the ballast but since it costs' almost as much as the entire fixture, I decided to replace the fixture.Is it ok to just replace the fixture or could the lack of a ground be the cause even after all these years of working properly?

To see if lack of a ground is a problem, all you need to do is touch the metal housing with your hand. If ground is the problem, it should clear right up.

Did you replace the bulbs with new bulbs because they were not working? If that is the case and it still doesn't work then yes, you need to replace the ballast. The lack or a ground on the motion sensor should not make any difference.