1FSTMAX

So i did a full power dash harness swap into my silverado, also while everything was a apart i added a UK3 clock spring and wheel. The harness i got from the donor sierra was not a UK3 truck. I did the clock spring, wheel, and denali gauge cluster. Only the lower 4 buttons work, however the volume, program and phone buttons are non op.

My question is are the steering wheel radio functions handeled by the BCM? or Radio? Meaning does the my steering wheel send a signal to the bcm then radio? or does the steering wheel talk straight to the radio?

At the moment im trying to figure what approach to take when taking it to the dealer. If GM pulls the vin from my truck, it will find a stripper model truck with basically no options; w/t trim. However i've slowly converted my truck to an LT trim and pretty much the only thing im missing is the TMPS and DL3 option.