Still sounds like a wiring problem.
You checked the face and radio connections and found them to be good, ok.
Have you pin check the radio wiring with a voltmeter. And while you are at make sure nothings hooked up funny.
If ground is ground and B+12volts is live at all time with +12volts and ignition +12volts has +12volts every time you tune the key to ACC or RUN; then you have a bad radio or this is changing when the radio is installed. That is you may have a wire grounding out when the unit is installed, so your pin out checks out but your radio acts up as soon as you install it.
Still I think you will find a bad radio or a wiring problem.
