One of the headlights on my 1930 Packard was not as bright when illuminated than the other lamp. While correcting what I believe was a poor ground circuit within the headlight unit I must have caused a short because when I turned on the lights, although they illuminated, I smelled a hot wire odor and quickly determining that the fuse block unit was very warm. I disconnected the battery and corrected the short in the lamp. I also noticed that the fuse on the fuse block was blown, but the headlights still illuminated which brings me to the point of this question which is how do the 1929, 1930, and 1931 Packard fuse block units offer any protection to the lighting circuits to which it is connected? These units consist of one 20 amp fuse conected in "parallel" with a wire coil which connects the two fuse terminals, therefore with the fuse removed, all lights illuminate just as though the fuse was in place. I don't understand why the fuse blew since the light continued to operate after the fuse blew before the short was corrected. It seems as though these fuse units offer no permanent protection. If I had not been working on the car and noticed the odor, presumably the fuse would have blown but the lighting circuit would still have been energized and illuminated. A series of photographs of this type of fuse unit can be seen on Tom Wilcox's excellent web site called "Packard Paddock". A 1930 wiring diagram that shows the parallel wire coil in the fuse block unit can be seen on the Packard Club website. I restored this car 35+ years ago and thought I thoroughly understood this car but apparently do not. Are all you 1929-1931 Packard owners as surprised as I am that your lighting circuits will operate without a fuse? What protection does this unit really offer?