I have a 94 jimmy dont want to lock into 4wheel hi will lock into 4wheel lo any ideas on what can be the problem

sounds like you may need the encoder motor

my jimmy also did this i disconnected positive battery terminal for about 20 seconds and this fixed mine.

When you shift, your foot has to stay on the Brake pedal, and trans in Neutral to do the Low range in and out.

its a warning your in 4 wheel drive so you dont forget to take it out when your on the road its good if its on when your in 4 wheel drive

No, you are corect, the system should be scanned to determine which component has failed.
Good luck.

I have the same trouble. It seems a relay is keeping it in 4wheel drive. I havne't solved the trouble yet. It may be a loose or corroded wire in the connector to the TCCM located in the passenger kick panel. Dealer part about $450 or more. For the moment I took out the fuse for the 4 wheel drive. It is located in the lower right hand side in the fuse the box under the hood. It disengages the 4wheel drive and I replace the fuse if I need the 4wheel drive.

Make sure you have activated your hubs.

4x4 selonoid switch in the transfer case was gone

I just had the same problem it is the position sensor on the encoder motor i think you have to replace the whole encoder motor though

check all lines some have vacum or small elc. motor on front gears