I have a 2013 2500HD with a Duramax. It's a Denali and has the 2013 top of the line radio that has the Navigation system built into the radio, CD/DVD etc. Large(for the day)screen and the small knobs at the top right and left of the screen. OK, hopefully I've described the radio accurately and you have a mental picture of the radio. Well, on my last vacation, somehow my charging cord(coiled type)for the cell phone got wrapped around the knob and it got yanked off to oblivion. Those little knobs aren't available through the factory parts system.....The dealer even tried to talk the radio re-manufacturing company into selling just the knob to no avail. After much searching on the internet and I had pretty much given up, I stumbled upon the right knob in "search images" and found that the correct knob can be purchased at:
OEM Radios Inc.
I took the chance and ordered the knob and it arrived yesterday and fit perfectly. It was ridiculously expensive @ $24.99 plus $13.99 shipping! But at least my pickup dash doesn't look like a big smile with a tooth knocked out.