2004 Envoy, radio took a dump, bought a take-out online but when I hook it up it says LOCKED , how do I unlock this radio? It is the wife'* Ride, Radios are identical, it lights up but do not know how to unlock it.
The 1-800 # does not seem to work anymore.
Any help would be appreciated.
Thanks Mike

I'd talk to who I bought it from. They should have the code.

Do this: https://www.wikihow.com/Unlock-Your-...heftlock-Radio

Let us know how it goes. I've heard references to this procedure but never had to do it.

Screengrabbed so future generations can see it if it disappears someday:

I tried this, the # does not seem to work anymore, need a dealer code witch I do not have, dealer want like $175 to unlock it, not worth it to me.
But thanks anyway
Mike

Did you try all five codes in Part 2 Step 2?