The search tune in my converted radio works exactly as it did when it had the OE Delco guts in it.
When you are all done, the controls work like they should, but to access the other features, (like channel balance) you have to do things like twist the volume to the left or right quickly.
This video shows how it all works. In fact, it's a GM Wonderbar radio, which I understand is the basis for our signal seeking radio.
I really suggest doing at least auxiliary input. I use my XM radio with it, along with a thumb drive full of music that plugs into a short cable. I have pre-amp outputs too.
Super John!! This is the kind of place I have been looking for - exactly what I want - conversion to stereo but keeping the original appearance and signal seeking function that works as new. I will get the auxiliary input as well. Great advice.