This is Pt 2 of this story.
In part 1 I showed how the rear wheels did not turn when AWD Diff lock was turned on, with car jacked up off ground, until throttle was applied, and then it turned slowly only.
The yellow AWD light had come on intermittently, with no AWD codes showing until a couple of days ago, which was P1822 = pump for 4wd motor wire open load. In data history, it had also said P1830 = Clutch torque tolerance lower limit, but this has not stayed active.

Sooo. in this part 2, we can now see that all wheels are turning equally even at idle, (both with diff lock off and diff lock on btw) and showing where the 4 wiring loom plugs are near the rear diff, which I simply undid, cleaned with aerosol cleaner and sprayed with WD40 penetrating oil, and replugged. This has fixed the problem physically and explains well the intermittent nature of the AWD warning light coming on without a code, until as above, it has been staying on showing 'motor wire open load' . I have not yet put it back on a scanner yet, but the AWD has not come on and test drive on dirt with diff lock off then on confirms proper rear drive.