So I have an 08 with a flatbed and it has cheap trailer tail lights. I bought some resistors and tried to install one but it says I need to connect the resistor to the blinker wire and the negative wire. My problem is I don't have a negative wire. I have a blinker a reverse and a parking light wire. I tried to put the resistor in line of the blinker wire and it made the blinker not work at all. The lights ground through the mounting of the light itself. I used a 25watt 6.2 ohm resistor. Does anyone know what the tolerance should be to make them blink correctly? Any help is appreciated.