want go into 4 wheel drive

I had the same trouble a few times. There is at the front drive train an electrical locking device. When you shift the leaver you give the transfer case the ability to drive the front drive shaft. It also requires a lock at the front to be energized. Now this is as simple as I can tell you but the fix is simple. ||Either the wiring is pulled off or rotten. Your local mechanic should know about this and repair it easy. Of to be adventurous and roll the vehicle up on blocks or ramps, block the back wheels to be safe and take a look . You will find it and see the wiring. If it is ok then the lock can be purchased for cheep and replaced. I soldered the wires and put back in a better spot as some tall grass had caught them the first time. Second time they were loose at the coil and full of salt like stuff. Cleaned it up and put on a dapp of silicone (not caulking) and all is fine. Remember although this is a simple note there are models that have a motor to do the job as well as a collar type clutch.

Be safe in your dealing with getting it up to be able to crawl under. You may like to have the aid of a friend to move the lever for you with the key on as you check it out.

good luck