This is the process I went through to add cruise control to my 2014 base Soul with manual transmission. This has been a long journey but its finally paying off. One lesson learned was to never let the dealer discourage you. So below are the simple steps to follow to add cruise control in.
Step 1: Order the parts. All you need here is the physical cruise control switch and a new harness inside the steering wheel so that the cruise control switch can be plugged into the clock spring. Don't let the dealer tell you that you need anything else. The following part numbers are what I ordered. I'm not sure if these change for different colors, but if your current wheel looks like mine in the photos, these are the ones you need. It should be a little over $100. If they are charging much more than that, they may be ripping you off.
Steering wheel harness: 56190-B2400
Cruise Control Switch (Black): 96700-B2100ASB
Step 2:Remove the wheel. Unfortunately, to do this right the wheel needs to come off. First thing to come out is the airbag. There are 3 holes around the side of the wheel that allow access to the airbag release pins. You need a small screw drive to push on the release pins all the way around. After all the pins are released, the airbag slides out (no screws or bolts). Then you can disconnect the wiring going to the airbag. PLEASE DO THIS WITH THE BATTERY DISCONNECTED! With the airbag out of the way, unscrew the nut in the center of the wheel. Use a Sharpie to mark the wheel and steering shaft so that you can easily line the wheel back up when reinstalling (you don't want to have the wheel ****ed when you are driving straight). I was able to remove my wheel without a puller. If you are not using a puller, be very careful not to damage the threads on the shaft.
Step 3: Build the wheel. At this point, you will need to completely disassemble the back of the wheel. After removing the 6 or so screws, the black plastic cover should pop off. Remove the existing harness and install the new one plugging in the connections to all steering wheel switches. I highly recommend that you test it, at this point. All of the switches use the exact same plug. So if you mix them up your audio buttons will be setting the cruise control and Bluetooth could be changing channels. We don't want that. Install the new switch and reassemble to steering wheel.
Step 4: Reinstall the steering wheel. Be sure to line this up with the Sharpie markings you made in step 1. Tighten on the nut to the steering shaft. Make sure all plugs are fully seated into the clock spring. Reinstall the airbag. MAKE SURE THE BATTERY IS STILL DISCONNECTED. We don't want that thing going off on you. Once the airbag is plugged in and snapped into place, you are ready to enjoy your new cruise control.
I hope this helps everyone out there who really wanted this feature. I'm personally very happy. My local dealer wanted $699 for an aftermarket kit to be added. This was less than 1/5 the cost and gave me factory results.