Sorry but I have to disagree because there's no way you can do this. LED's are directional in that they have a positive and a negative unlike regular bulbs which aren't polarized. I give you that. But regular bulbs can only be installed one way because they have locating pins and they are offset. The only way the LED bulbs will fit in a 1157 socket would mean they also have locating pins that are offset. Even if you turned them around your not reversing the polarity. You'd just be switching from one element in the bulb to the other because 1157's are dual filament. Ground remains the same connection which is to the body of the vehicle which is at negative potential. The only way to reverse the polarity is to hook up the battery backwards to make the body at positive potential.