New Ignition Cylinder Truck wont stay running

Ive read through the other similar posts but cant come to a definitive answer to my question. I have an 03 tahoe that has issues turning the key unless it's in the exact right spot. In addition to the difficulty turning the key, my radio has a tendency of turning back on after the key is removed until I put the key back in, turn to acc, and turn it off again. I figured this was a sign that I needed a new lock cylinder so I ordered a replacement which came with new keys.

After putting the new lock cylinder in, the truck will start and then immediately die, indicating likely a passkey issue. When the truck turns off though, the passkey light goes off immediately. I know all about the usual relearn sequence of key on, try to crank, wait 10 minutes until passkey lights turns off, key off wait 5 seconds, try again and on 4th try it will start and stay running. All that is good and all but my passkey light doesn't stay illuminated, it doesn't flash, it just goes off. Is there a way to "teach" the ecu to work with the new cylinder and key?

Also, after putting in the new cylinder, the radio just never turns off. Key in, out, turned, not turned, I even put the old cylinder back in and I can't get the radio to turn off now. The truck will start and stay running with the old cylinder in, but the radio issue went from an annoying process to switch it off to not turning it off no matter what I do.

I know the cylinder has a resistor of sorts in it that is likely causing my start but no run condition, but I don't know how to go about fixing it or swapping something from the old cylinder to make it work.

Anyone have any ideas for the lock cylinder issue as well as the radio issue? Thanks for your time.

Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

I cannot personally assist you with your issue, but other members of this Forum much more knowledgeable than me in this area will chime in.

I assume that you do not have access to a quality bi-directional scanner, as that would most like point you to the source of your issue.

I do not have immediate access, although I have requested one for Christmas. My mobile mechanic I use off and on has one but getting him over here has proven difficult as he lives about 45 minutes from me. I dont have any pictures of the vehicle just yet as I'm still working out all the little things wrong with a vehicle that's old enough to drink alcohol but I'm getting very close. New front end, rear hatch door lock actuator, new lift gate hydraulics, new transfer case, rebuilt transmission, rear main, oil pickup tube o ring, oil pan gasket, oil pressure sensor, new stepper motors in cluster, leds in dash and cluster, completely gutted interior down to metal for a deep clean, new ignition cylinder, new ecu, new steering column shifter spring, cleaned contacts on door latches, new ac compressor and all related components, new headlights, taillights, brand new tires, new radiator ... pretty much any little thing I could do while i wait patiently on my mechanic to rebuild the transmission I hired him for back in April -_-

At this point I've learned enough about the 4l60e that I'm confident i could do the rebuild in a fraction of the time it's taken him to do it, diagnose the issues, and now rebuild again ... I just lack some of the speciality tools I'd need to do it right. I have thoroughly enjoyed-ish tearing down and getting into the nitty gritty of this 5.3l vortec though ... all of my previous experience has been on the 5.7l 3urfe toyota motors, which I love, but the tahoe has been fun and it seems like a decently well made motor if taken care of properly. These electrical issues are quite frustrating to say the least, even with a background in electrical and computer engineering. I'm long overdue for a good bi directional scanner though so hopefully the fam makes good on that request this year