Join Date: Aug 2016
Location: Branson Missouri
A bad earth/ground is your first option to inspect, then crossed wires, then the bulbs, but if you have LED lights front or rear, they can also cause problems.
Crossed wired is a terminology that's confusing since all wires are insulated, maybe a pinched wire is more appropriate?
Also, I would worry about the headlamp flashing even if it does seem beneficial, & you won't pass your next inspection with it that way either!