Turn signals don’t work when headlights are on

Ran a jumper from the core support to the bulbs pig tail base and YES, it works. Did not flash as fast as the driver's side but it definitely works. Can these pigtails be separated from the housings ? I have a few spares that I can just check to see if they work as well. On another note what size wire should I run from the battery negative to the core support ? Thanks for all the support everyone.