Your videos bring back memories of the lightbars and sirens I used to have. While driving a Nyc Transit Authority suburban I used to visit that Nyc vehicle aution on what I think was Kent ave in Brooklyn in the early 90's and purchased 4 of those Nypd Aerotwinsonics and 4 red Federal Signal Teardrop Fireballs. I still have 2 of those Fireballs. Regarding your Aerotwinsonic's flashers not working,I think the flasher is the model Wagner #537 Alternating flasher. I just subscribed.
So I never did an update of this bar but it was the 537 flasher and has since been replaced. This bar has since been restored, and I will be making a video on it in the near future.
