I just installed my Frontier Bumper replacements and on the rears I have the spot for reverse lights. Instead of using the cheap ones that were included I went and bought some LED ones.
While trying to wire them up I took out my tail light assembly and tied into the reverse light from there. I spliced the black wire from the bumper wiring harness to the white and red wire from the tailight harness, and the white(ground) wire from the bumper wiring harness to the black wire in the tailight harness. There is a third(red) wire that I didn't use on the bumper harness. I was able to get the cheap bulb lights that were included with the bumper to work properly, but when I would hook up the LED ones to the power source I couldn't get anything.
Do I need to add a resistor to the wiring? or am I hooking into the wrong places all together?

 

Try reversing the LED wires or hooking them directly to a battery for testing.. Some LED's will only work when properly polarized..

 

Hook the red wire up instead of the black one and that should get the lights working.

 

You were correct bigjohn. Tried that and everything worked. Thanks for the help.