Today at a light with my left turn signal on the trailer brakes started coming on and off in sync with my signal. So when I took my foot off the brake to go the trailer would jerk till I shut off the signal. Went to my shop unplugged the trailer and noticed with the left signal on all the lights flashed like my hazards were on, even the bed light on the back of the cab flashed. If I push the brake the green arrow on the dash stops flashing and just stays green. I have no burnt out lights on my truck or trailer. The right flasher performs as should. Time to get out the multi tester meter!