The computer is not interchangeable. It has to match all the parameters of the vehicle for it to work...i.e....95, auto, etc.. if you was a plug and play computer, as much as I hate dealing with them, You can take it to Auto Zone, and they can hook into it and tell you exactly what it is, what it's parameters are, and a new 1 through them is around $300.
If you are searching for one in a salvage yard, the year, the engine size and the trans and all the options in the jeep (Doesn't have to be a YJ) have to match for the CPU to work with her motor.
'87 YJ, 4.2L built and bored, 8" of lift, 8.8 rear, AX15/NP 231J, Tom Woods drive shafts, Flat fenders, 12,000LB winch, Custom bumpers, Rattle can paint job. Never completed...