GX45H diff lock not working

[TheFarmerInAdell]

I needed to use the diff lock the other night and it didn't lock the diff. It's an electronic push button on the fender. The light on the dash came on, but the tires didn't lock together. I've noticed in the past that the light on the dash is sometimes on half brightness without the button pushed, and becomes full bright when the button is pushed. I'm guessing the actuator is bad, but I wanted to see if anyone else has any ideas on what to look for? I haven't really dug into this too much yet, because I just noticed it. I probably won't have time to look at it at until the weekend.

Anyone have an image of the actuator assembly or a wiring schematic for this system? It seems that McCormick stuff is hard to find.