Tail lights

I've been having issues with lights on a
truck I recently purchased, I have been
able to tackle a lot of the issues by
replacing brake switch, turn light switch,
head light switch and the combination
flasher in the cab and also the relay in
engine bay for brake lights, currently
everything works as far as turns, hazards,
running lights, head lights(hi and low) the
problem is when the running lights are on
the rear turn signals flash back and forth in
both directions of the turn switch.