ok if im understanding you wired the wires togeather that sounds like the problem. if you took a 3 wire system and made it 2 wires the power is going to backfeed to the otherside. ive never done the mod youve done but adding a relay comes to mind for the brake lights, however im thinking even with a relay when the brakes are on and you turn on the turn signals both sides are going to flash dont know if adding a diode may cure this.. perhaps calling the manu. and asking them.WIREING GURUS please chime in
from the jeep you have three wires? hot for brakes, hot for blinks and grnd? or just hot and grnd? if the 2 wire is the case maybe you can get one of those plug in harnesses for trailer wireing and use that, i think that splits the single hot and makes it a seperate hot for brakes and another for blinks