Question about a few things
 

I just bought a 1992 XJ with 180k on it 2 weeks ago. It runs great, but there are a few problems.

1. It seems the back-up light socket it rusted out; where can i get one? Are they expensive?
2. Im not sure if the 4wd works; is there any way i can test to see if it does? And how exactly are you supposed to put it into 4wd, ive heard a few different theories.

1- Most parts stores carry replacement light bulb sockets. under $10 IIRC.

2- engage by lifting the floor mounted lever while rolling slowly >10MPH and most have a dash light that comes on that indicates part-time 4WD. If you continue the lifting of the lever you can get to 4LO which is very similar to a granny low on a truck 4 or 5 speed manual. Unmistakeable. The 242 also has a fulltime option.

Please go to your profile page and fill in the info about your Jeep so we know what you have in the way of engine, tranny, transfercase and differentials. This will help others to answer your questions in the future without haveing to ask you more questions.

Oh ive seen things like you have to be in neutral.. park.. and ive also heard that you have to be going around 5-10 to engage. Thanks for the help

I think it is the way that different 4WDs engage. I had an old Jeep with lockout hubs that had to be stopped to engage but then you had to be stopped anyway to lock the hubs. So different vehicles work differently.