I did use the plug and play harness they provided, just connect the resistor to the red and white wires on the harness they provide and connect the reverse to the black wire in the oem loom, which is the ground, depending on what year jeep you have the reverse positive wire can be a different color so you need to put it in reverse with the key in the acc position and take a tester and see which wire the power is supplied to.

 

For those that have installed these without the resistor, did it give you the bulb out message on the dash or just blink fast? I wouldn't mind the fast blinking but don't want to see the message every time it gets started. This is on a '12.

 

Yes, you will get a message saying light out because LEDs draw a lower amperage making the system believe there is a light out, I've heard of people reprogramming a part of the CAN-BUS to have a lower amperage draw, but resistors are a much simpler solution.