LFB has taken to blowing no.2 fuse (the pilot/tail light circuit). I'm not worried about that because I'll find the source of the problem sooner or later. What has me mildly puzzled is that when the fuse blows and the tail light goes out, the BMU doesn't react. The red warning light doesn't come on. I tried another BMU with the same result. Conclusion: my understanding of how the BMU works is incorrect. Can anyone enlighten me as to its actual functionality please?

If the fuse blows the BMU react the same way as you haven't switched on the light.......
no voltage input, all is OK.

If the bulb blows you still have voltage input at the BMU, but no current flow...
warning light shows.

Thanks Inge.