Diff Lock Relay was not bad after all. It
apparently makes a difference if the pinout diagram you are using if for the relay side or the plug side. Anyway....
After some hours of testing and diagnosis, I think there is a problem with the switch in the CDL control motor between pins 5 & 6. I narrowed it to this because it was easy to activate the CDL from the driver's kick panel plug C4 with wires and a 9V battery to CDL control motor pins 2 & 3 (pins 1 & 4 at the relay. (You test these things with 9v per FSM) Similarly with 9V applied to CDL relay pins 6 and out pin 5, the relay operated properly. So I figured relay pinout 5 which goes to CDL control motor pin in 6 is not competing the circuit. Ideally I would test CDL control motor pin out 5, but its on top of the transfer case. So what I did was hook it all up and ground relay pinout 5, and voila, CDL switch makes it work. I buttoned it up leaving a temporary wire into relay pinout 5 so I can test the theory if it fails again - because, oddly, its working now in stock configuration.
Summary: I think after the CDL control motor unlocks (which it has never failed to do), the contacts inside that would close the circuit for the next lock cycle, do not reliably shut.
Or I am completely wrong.