Sounds like a lamp matrix issue. Those lamps are all on the same column, along with the Right Lock lamp, so that would make the most sense.

Is the Right Lock Lamp stuck on too? If it is, then the entire column is stuck grounded, which is likely a bad TIP42 on the MPU.

As a test, pull connector 1J6 and turn on the game and see if those lamps still light up. If they don't, then you've ruled out random ground path wires touching any of those bulb sockets to complete a ground return. If that is the case, the issue is on your MPU. Suspect parts would be Q17 transistor, Q25 transistor, or the logic IC U53 being stuck high. The most likely is a shorted TIP42, Q25.

If you have a multimeter handy, you can probe Q25 TIP42 and see if it is shorted. Put the black lead on pin 1(far left leg). and probe the center pin and far right pins with the red lead. You should get like .6 on the meter. If you get 0, then it is shorted.

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Awesome. Good work!