ok so here is my problem when ever i shift into 4wd on my 89 xj the check engine light comes on and my 4wd will not engage any ideas

 

I am not sure about the check engine light but is your 4x4 use the vacuum disconect? If so is the Vacuum functioning and the fork moving?

 

mo idea how can i find out

 

If you look at the passenger side of your front axle and see something like the picture below then you have a vacuum disconnect.

If thats the case engage your 4x4 and open it up (be prepared for a little gear oil) and see if the fork has engaged the 4x4. You should see to axle pieces that have been connected by via the fork

 

ty ima check that out as soon as i get home from work