Well, then it is not a polarity thing, but the LED lamps are wired wrong ?? The green is 12v pos to park light,,, purple and red are 12v pos to each turn , the socket is grounded,,,I have to think your idea, is just a brighter park light,,, as it is connected to the brighter element in lamp, ,, which means a dimmer turn light,,,, The park light element is dimmer than the turn light element normally? The rear has no issue,,, LEDs flash fine,,,,I am thinking if I put LEDs in the front, and Regular lamps in the rear,,, the front LED's and rear lamps should flash fine,,,because I have just the opposite now,,,, LEDs in the rear , regular in the front,,,,,turns fine,,, just will not turn when I change front regulars to LEDs. [all 4 LEDs]
