4wd wont engage any help will be appreciated

[geeves]

I dont know your motor but being petrol it takes the vacum straight from the manifold. If this was bad you would have no brakes. Its a matter of working through things one step at a time working backwards from the clutch to the ecu solinoids.
How do you know it isnt working? It might be iit hasnt detected slipage so hasnt activated

[Natek235]

HI all, I'm also having trouble with engaging 4wd. I have a 96 isuzu wizard, motors a 4jg2 turbo deisel. Model# UCS69GW. Now I've only had the truck a short while, and have been getting it back up to roadworthy standard as the previous owner was careless. So today, first time taking it off road and 4x4 wouldn't engage. Manual locking hubs, gear shifter from 2wd to 4h and 4l. No lights on dash no nothing. With gear in 4wd position the shaft won't turn like it does in 2wd. I'm unfamiliar with 4x4 so any advice on what I should look for or try next would be appreciated! Nate

[geeves]

Manual hubs on a wizard will be aftermarket. They are a mod done by a previous owner to improve ecconomy but the amount saved is hardly worth it. Have a look underneath to see if there is a second housing on the front diff as a first step