I have a stock 08 grand prix, Im trying to get my 3rd brake light on spoiler to blink when brakes are pressed. Today I went and bought a flasher, I have 2 wires coming off light, white and black, I cut the white wire and ran the 2 wires (each side) to the 2 prong flasher, but the light just stays on, wont blink..So I tried the black wire, ran each side of black wire to flasher, and reconnected white wire, lights turns on, but no blinking..What can I do to get this thing to blink??