Thanks for the tips on the wiring.
What I meant by "continuity" is that my voltmeter does show that there is continuity at the mentioned plug.
I was wondering about the ground at first too but I was thinking more than just the taillight would be bad if that were the problem.
After stewing on it for a bit, here is what I did last night...
I wired-up a test light and jumpered it into the socket at the end of the wiring harness at the battery. The brakes both triggered the light at that point and the running light connection was working as well. So, the problem is most likely either in the socket and plug at that point (they are looking pretty corroded) or in the wires themselves going back from there to the light.
I am thinking of taking the plug off and splicing in a new one first since they are looking pretty nasty. If that doesn't fix it I will run a new set of wires back to the tail light. Off to the auto-parts store...
07 Husqvarna TE250,07 VStrom 650, 92 Suzuki DR350S
"Go soothingly on the grease mud, as there lurks the skid demon!" -- 1962 Honda Safety Rules