I can do a write up when i get time. Its very simple.
I use the Dominator ECU's and just build a harness.
Most trucks keep everything functional. The only issue is 2003+ has Serial data for AC request. So i just modify it so the AC is controlled by the holley.
The 99-02 has a 12V AC request so its simple.

 

The holley is so simple to tune, I've been able to tune my NA LS swap

 

I would be interested in a write-up on integrating the Holley into a GMT800/900 platform... Not that I can afford one of those systems, LOL. But good information to know

 

Did you try pulling the radio and amp fuses? This worked for me.

 

Dorman DDM's cause issues as well.
Ive had to pull all the fuses except whats needed to power the PCM and OBD port on some 2004-2005s.
After all that trouble i just hook up my rigged external Serial wire to PCM and no more possible issues.

 

DDMs?

 

Driver Door Module (the door switch module).