I ahve a 92 XJ. Cruise has never worked. I checked fuse 20 and it is fine. Flashers and brake lights work which from what I gather tell a bit of health of feeding fuse and brake switch. Also, the trand TQ unlocks at highway speed when I tap the brake. So, a few questions.
1. Anyone have a schematic of the cruise control section?
2. Where is the cruise module located?
3. I found a schematic for a 1990 online. It shows a 4 amp inline fuse that says it is under Instrumetn panel. Anyone know if my 92 has this fuse and where it is?

 

I dont have the answer to your questions but I do have a suggestion. See if your plastic/rubber fittings/lines have leaks in them. Mine cracked and I cut the sections / elbows out and put rubber hoses on them and my cruise came back to life. It has been going strong for 7 years now without issue.

 

Oh, I forgot to mention my AC, heat, defrost settings all work so from other posts I have read that seems to confirm I dont have a vaccum leak. Or is that not the case?

 

Might not be the case, it takes less vacuum to operate the a/c stuff than it does to operate the cruise. Mine is one such piece of anecdotal evidence.

 

Ive been tryin to figure mine out for a while too.
https://www.cherokeeforum.com/f2/try...control-61441/
Let figure this out!