I have a 93 GMC jimmy 4x4 SLT - 4.6L we have had a lot of snow recently although even without snow, when off road my 4 wheel drive is definately used, when needed to access our cottage. (off road )I went to engage it the other day and the 4 wheel drive switch light came on green in 4 high then flashed off, it will not stay engaged. However the truck will engage in 4 low (orange light) and you can feel it going in. Question therfore is why wont it stay engaged in 4 high? also yesterday there seemed to be a vibration in the front when put into 4 low this just started. It is also hard to get out of 4 wheel drive once its put in. My husband took it out yesterday and did not think the 4 low had engaged yet showing on dash it was as he began sliding around at the back end.
I recently put over $600 into the front end in new parts, tie rods, upper and lower ball joints, alignment etc.......(as in previous post)
Any diagnosis would be appreciated. Thanks in advance.

P.S the truck is driven daily to and from work.......

 

You have any luck on what was causing your problem? I have a very similar problem to yours. I have had to push the button to go from 4wd to 2wd 100's of times before to get it to go back. Any info you can provide would be appericated

Chris

 

i have a '99 jimmy same issue i changed the dash switch but no diff. and found it to be the encoder motor on the tranny...i know some have had success with switch and its cheaper...hope that helps.