Cain Marko

So as the title vaguely states I had a battery die on me and now the running lights(heads/tails) wont light up, but the tail lights work when the brake is engaged or turn signals activated, just wondering if any of you have run into this little issue so I can have a better starting point than point testing every wire in the harness. Thanks in advance, oh and harness is all stock, only thing thats been changed was I put a MNNTHBX turtlehead LED tail light and it worked perfectly until I installed another battery.