Why can factory bumper sensors be added during repairs but not as dealer add ons?

[govandlaw]

Why can factory bumper sensors be added during repairs but not as dealer add ons?

[Fifty150]

That's something you have to ask your dealer.  Any dealer should be able to add them.  Order and install, right?

[DonShockley]

I*'m just guessing here, but lots of the optional items and even routine things like door locks and window switches rely on individual modules scattered around the car to accomplish those tasks. You would think they would just have a master wiring harness and you could just attach the needed modules, sensors, etc. to get the features you want. But it appears that's not how they build them. If it's not a factory feature on your individual vehicle, they leave all the wires and interconnections out entirely. They probably save a whole $50 in parts cost doing it that way.

 

Replacing sensors if all the underlying hardware and connections are in place is easy. Adding all the extra wiring, connectors, and modules on a fully built vehicle can be nearly impossible. Here's the section from the wiring manual on my 2015 where you can see all the stuff that's needed in between the bumper sensors and the speaker to make it all work. Plus there's ususally some software changes needed to control it all too.