I was wheelin my stock 2000 GV yesterday, and high centered on a little hill with a big rock stuck under me. When I got out finally my 4WD does not engage, and the 4WD light does not come on either. I shift into 4 low and I'm only running the rear wheels in my lower gears. 2WD works just fine. I took a brief look at my under carrage and so no visible damage. If anyone has lost their 4WD like me and fixed it help me out!

Weird, at first I thought you were reposting from here http://www.zukiworld.com/forum/index.php?topic=12599.0
but that was a different user.  I would watch any suggestions he gets as the TCase and driveline are basicly the same except that we have an actuator in the front dff instead of locking hubs.  I assume your not noticing any odd noises suggesting something is broken in the TCase or axle.

If everything else seems/looks fine I would check the acutator mechanism for the front diff.  Their should be a hose going from a pump in the bumper to the diff, you should test this for pressure/leaks.  Without pressure your diff won't engage, and the 4wd light won't come on. 

First things first this happens all the time.

Get under the truck there is a vacum line on the frame near the diff check it they pop off all the time.

First things first this happens all the time.

Get under the truck there is a vacum line on the frame near the diff check it they pop off all the time.

Josh is much more succinct  .  Obviously there's no pressure if the hose popped off.

lol just went wheeling a few times and guys were like WTF my trucks fucked. Mud hits or dirt and pushes it off clean it and put it back on put it on like 1" and zip tie it and push it up a  bit

i have a similar situation with mine.

i replaced all the rubber lines from the pump to the diff, but that didn't do anything.  the pump can be heard running for about 10 seconds when i shift into 4WD (can only hear with engine off), but it doesn't build enough pressure to engage it - probably a ripped diaphram.

i hooked up a bike pump with a gauge to the line and it physically engages my front diff at 5psi like it should so the air pump is likely the problem.  it's $280 from my dealer so i'm holding off for a better solution to fix the problem.  for now i have a 2WD tracker.

Well Josh was right, fixed it. It was hell getting of the mountain in 2WD. I would not have high centered if I had a lift kit Josh....Just kidding  Thanks for the quik fix.

Kiernan