Look on the outside lights on each side. The fiberoptic cable is less flexible than what we have now. It was mounted to a bracket that holds it very close to the bulb.
It does not look like a wire - more like a hard plastic tube. If the end is dingy, try cleaning it with some window or plastic cleaner. I guess the end at front could be dingy as well.
By the way, even when it's 100%, don't expect to see it in sunlight.
Going to a forum rally last October, I was running late and ended up traveling after dark. A few trucks and cars honked as they went past. Thinking they were Airstream admirers, I smiled . . . and then I looked for the light indicators. They weren't there.
And that's how I ended up spending the night at a Flying J . . .
So far, I'm batting 50/50. Half the time I make it to where I intend to park, and half the time I end up broken down at the Flying J. Bless 'em for their welcoming, bless 'em for being where I need them, and bless 'em for keeping me informed about their showers.