I had the same issue, the knob was just made of black plastic.. Line 6 did not want to send a new knob since I m not living in the US, so I had to send the guitar back to the supplier for replacement.... Well the new one is better, it does illuminate somewhat. Some modelnames shine better than other. And there is still a lot of black plastic in the wrong parts of the knob. But I'll accept it.. With some difficulty because you suspect something else from a guitar in that pricerange.
By the way, I adjusted the height by inserting a little piece of matchstick, that worked fine for preventing the shaft of the swich going further in then required...
