It's a lost cause so you need to give it to me.

If it's coming on and off at pretty much random times, I'd check the connection and the bulb. The Stern sockets aren't the greatest so it could be a case of the bulb just being lose in there. If that's not it, maybe swap bulbs to see if the problem moves to the new location, if so, it's the bulb.

If that all fails, then I'd look for a pinch in the wire somewhere between it and the board as there may be a small break in the wire (but not through the insulation) that is causing it to be flaky.

I had the game a while back. Those letters are earned and carried game to game I believe. Does it ever light during game play?

That's a game feature. MUSTANG multi-ball carries over from game to game. You (or a player) earn those letters.

It's telling the next player all they need to do is light U for a multi-ball. Once it's rewarded all the letters will go dark, and letter by letter they will be earned again.

You can turn that feature off, but collecting all letters in a single game would be very difficult.

One more thing. When the car is rotating, the letter closest to the player is what is eligible by hitting the scoop.