Waiting for someone with dif diagnosis experience....so let's just call this a bump because it's not really useful.
I've had mine out and in, but other than a bad vacuum line that the po had to deal with it's been working great (knock on wood!).
The yellow circle is the 3rd bolt you have to undo- and then lift it up and out of the hole in the cross member- if you end up needing to take the whole stupid thing out.
The actuator is the light brown dirt colored thing behind the passenger side axle tube. Easy to find because of the big round vacuum diaphragm with 'L' shaped hose barb. The vacuum lines go into a set of metal lines bolted to the top of the diff. It was bypassed with a vacuum hose. Vacuum lines for the 4wd can be found on the driver's wheel well in the engine compartment below the moo-box.
Is it weird that the light is simply dim? I don't recall correctly, thought it was supposed to blink or something, not go dim?
Will love to hear how this gets figured out!