These are old prehistoric values from a 3rd party model but the lights are working. Don’t forget to disable the modern stuff in your system file.
[ELECTRICAL]
; LEGACY
max_battery_voltage = 24 ; ###
generator_alternator_voltage = 28 ; ###
max_generator_alternator_amps = 60 ; ###
electric_always_available = 1 ; ###
flap_motor = 0, 5, 17 ; ###
gear_motor = 0, 5, 17 ; ###
autopilot = 0, 5, 17 ; ###
avionics_bus = 0, 5, 17 ; ###
avionics = 1, 5, 17 ; ###
pitot_heat = 0, 2, 17 ; ###
additional_system = 0, 2, 17 ; ###
marker_beacon = 1, 2, 17 ; ###
gear_warning = 0, 2, 17 ; ###
fuel_pump = 0, 5, 17 ; ###
starter1 = 0, 20, 17 ; ###
light_nav = 0, 5, 17 ; ###
light_beacon = 0, 5, 17 ; ###
light_landing = 0, 5, 17 ; ###
light_taxi = 0, 5, 17 ; ###
light_strobe = 0, 5, 17 ; ###
light_panel = 0, 5, 17 ; ###