Synopsis of problem:
After engagement of center diff lock via dash mounted button (you can use the hazard switch if center diff button not readily available) you will notice that the center locker "whirring" noise is present, but the ABS light and the Center Diff lock light do NOT come on.
Thus the computer has not been given the go ahead to allow locking of the front and rear diffs.
Cause (in my case...and probably Seto's too):
Bad transfer indicator switch on top of transfer case. This is NOT the switch located on the rear portion of the transfer case that is normally unplugged when wanting high range center lockage. This is the switch located on the FRONT output side of the transfer case approximately at 11 o'clock when facing towards the rear of rig from the front.
To test if transfer indicator switch is bad:
Unplug cable leading to it short it with a paper clip (or any other hi-tech device suiting the same purpose). If your ABS and Center diff light appear after pushing your center diff lock button, then you pretty much know the switch is bad.
Solution: cry...no not really, that never solved any problems :) Call your friendly Toyota dealer and ask for part number 84222-12010 (description: "switch, transfer indicator"). This part also comes with new washer. My local Toyota price with discount is about 50 bucks.
The switch is pretty much a sealed unit, so there is no "fixing" of the old switch. After you remove the switch you can test it if you like for even more verification (or if your anal like me). Take an OHM meter and put a lead on each of the switch's electrical prongs. In the natural state there should be no readings (switch is open). When switch is closed (just push it with your hands) you should see no more than .1 ohms of resistance (almost a fully clean closed circuit). Bad switches will show 100's of ohms of resistance in the closed position.
Hope this helps others, as I did not find this in the archives :)
I apologize if I insulted anyone with being to layman in my writings, I also apologize in advance if I left any detail out :)
I would like to thank the group as well as Bob G and Seto for their aid in troubleshooting and/or verification.
I apologize in advance if I forgot to thank anyone else directly, as I didn't mean any harm ;)