iPhone flash always on dimly

My iPhone 4's flash light is always on, very dimly, all the time. I can't get it to turn off. I see this is a common issue, I have tried a few things:

1. Rebooting iPhone.
2. Letting battery run out. (The light stays on even when the battery has died, so I guess there is some reserve power there even when the iPhone says the battery is dead.
3. Tapping the iPhone on the back (some people have said this works).

Can't seem to fix it. I suspect it is making the battery drain faster. Any other tricks to take care of this without replacing the camera?

Thanks.