Which is called the shift-on-the-fly or SOTF actuatorWhen you engage 4WD there is a motor on the front passenger side drive shaft that slide over a spline and locks up the front drive shafts.
Yes under normal conditions that would be true, But that front motor is in a vulnerable place and often seizes or does not work (as mine did). So I just disconnected the wires, made sure it was always locked on, and got free wheeling hubs. Problems all solved.But when you take out the 4x4 fuse the front axle will spin freely an when you put the fuse back in the 4wd light flashes until you roll forward you can hear the front axle lock in
Don't have a Great Wall but ...It's weird because when you put the 4x4 fuse in just with the ignition on the front hubs lock in without the car even going