When you say reverse wires,,,, was that at the flasher connector ? I see there is a pigtail flasher,,, that says it is blind to polarity,,,, aka,,, Bipolar in a good way,,,, but that may still try to put negative voltage to the lamp,,,,,so,,, rather cut and spice,,,,,,maybe this::
United Pacific Polarity Reverser Adapter For U.P. 90650 Turn Signal Flasher | eBay