Polaris does it weird -- the brake pedal switches the NEGATIVE lead instead of the positive lead (which is what everybody BUT Polaris does). With a normal bulb it doesn't matter, but LEDs are polarized.

The resistor trick works great. I'm running the same LED's as listed in that article link and they work great. I used 330ohm (I think?) resistors instead of the 470ohm ones, as I wanted the running lights a little brighter.