Ive read through the Unlock Nav after install thread several times but I must be missing something (unless it is no longer relevant due to age)....

I'm working on my 07 escalade...original radio was a YQ3

I installed a U3R nav unit (part number 20807245)
I did not install rear view camera yet
I have tried programming using mongoose cable, nexiq USB link , and a tech2 in all modes....all with same error so I think it is me doing something wrong

I started by logging into sps and selecting vehicle
then selected replace and reprogram
then I select radio (U3R.....not sure if this is where I am going wrong or not)
selected part number 20807245
selected 25854978 for tuner
selected 25872948 for audio
selected 20823186 for equalizer
selected 25836947 for rear view camera

(I got all these numbers from reading calibration ID with tech 2)
When I select next to start with programming, it fails and I get an error saying communication could not be established,
failed rad-radio pre-programming

.......
I tried selecting YQ3 radio to start but could not select proper part number for radio...
when I tried using tech 2 as remote, it only showed YQ3 as radio choice
I tried picking random calibrations for tuner etc to see if anything wold react different with no luck

not sure where to go from here, tempted to put old stereo with stuck dvd back in but Im too stubborn

any suggestions??
thanks in advance