I have no idea,
but I will offer that on my numerous 2033 MOW diesel pantograph locos with flashy lights-
the circuit is wonky / or the components are wonky, but, they seem to inevitably fail, and
are a PITA to trace the circuit/part
what I have done, and YOU can too...LOL...is to replace the bulb with flashing LEDs, suitable for direct track voltage and wire directly- ie with resistor and diode if desired),
I used 5mm which fit pretty closely to the existing LGB 5 v incandescent sockets. unplug the LGB bulbs and stuff the sockets in the cab, or whatever , and run the LED leads to track
these have worked really well for me, and give a better effect, IMHO, as each LED has its own blink rate-almost but not quite identical to any other LED , and so one gets a very authentic looking out of sync independent strobe flash effect.
I used blue, which is very striking, in all but the brightest sun, but any flasher color works . the advantage is you keep the loco original, bypass the flasher stuff and have a reversible substitute-
otoh....could be a blown bulb...but if it isn't, just a inexpensive solution.