I doubt the dealer will reprogram it for you, and I doubt an aftermarket stereo will respond to the buttons.

 

I should beep out the steering wheel and the harness underneath the steering wheel when I have a chance, but I'm not even sure if they are simple switches or using a more sophisticated communication method.

 

my truck is an 08 basline truck.i bought the steering wheel off rock auto.dont remember if it came with the internal harness or if i bought it off gmpartsgiant.com.i installed everything and the cruise worked without reprogramming.i install an aftermarket radio and had to buy an axxess module for the buttons to respond.now everything works and i didnt need to bring it to the dealer.now i cant speak for newer trucks .good luck!!!

 

I was able to successfully do this on my 2013 express 2500, a junkyard OEM steering wheel with cruise control + radio controls, an aftermarket stereo and several adapters (Axxess GMOS-LAN-01, Axxess ASWC-1). Not all the buttons work, but the important ones do (volume, next/previous song).

I had to give the dealer the part number of the regular cruise control only steering wheel. When I gave them the correct (cruise control + audio control steering wheel) part number, they weren't able to reprogram it. My dealer charged me an hour of labor to reprogram the BCM ($170).

I never tried the audio controls before the BCM was reprogrammed, but I suspect they might have worked.

 

I came at this one sideways. I went to a junkyard and pulled a head unit and the steering wheel buttons off of a 2011 equinox I think, 60$. Slapped the buttons on my existing '09 Express steering wheel. Little bit of Dremel work required to make access for the wires and screw holes but wasn't too bad. Used the wiring harness out of the donor vehicle and repinned it into my existing steering wheel harness connector on top of the one that was already there with horn button wires, had to splice the ground. Swapped the VIN chips in the head units so that the one from the equinox thought that it always lived in a an Express in the first place and didn't Lock me out of the radio. And it all just worked, Didn't have to do anything to the BCM. No reflash, no dealer, no nothing just Plugged it in and went.