2006 Chrysler 300C
 

I have a 2006 and it came without the backup sensors in the rear bumper.
I would like to install the rear sensors. Now does the 2006 already come with the wiring in the car already? or do I have to install the wiring from front to back?
I have found a bumper with the sensors and I just want to swap it out to my car. Please let me know

With modern cars, you will need the wiring harness, front to back.
Also, you will likely have to take it to the dealer for a programming update, to get it to work.