The source is the one we discovered to work best 10 years ago right off of the split T we created from the line at the intake manifold with the green/white in-line valve and has not been changed in the past decade, it just stopped showing boost negative or positive.....nothing. I'm sure there is a pic of it in one of my build thread or DIYs. The gauge illuminates, but the needle never moves whether at idle, under load or any other time. Since there is no deviation I assumed it is a failed component not sending the signal and this is relatively a simple gauge with not many variables to cause the concern which led me to believe that the Pressure Sensor just finally burned out.
I know you know your stuff and I'm glad you responded. It's good to see you are still involved and good to hear from you brother. Do you still have your ride? I see it listed under your avatar.
Columbus Body Works / ARK Performance / Modern Automotive Performance / Forged Performance