Thinking about this, bypassing the JB by jumping the blue wire to the battery won't do you any good if you're currently getting 12v out of the JB on pin 17 (the new location of the blue wire after the blue wire mod), which you should be if the tail fuse is good like you claimed. You'd be bypassing good circuitry, and the problem downstream would still prevent the headlight from working.
short story: check for voltage there before rewiring.
Will do. Should be a constant 12v out of the blue wire with the key on, right?