Cross body wiring harnesses

[JeepComanche89]

So I am aware that in 1991 Comanches adopted the HO version of the 4.0, along with the OBD1 electronics. 

 

My question is did the 4 cylinder models in 1991 also have the revamped computer system? Any finally if I have a 1991 comanche HO motor and engine harness, would I be able to plug the HO engine harness into the crossbody harness of a  1991 comanche that currently has a 4 cylinder motor?

 

 

I'm honestly at a loss because I cannot find any info, and worse I do not have either of these things to look at in person. Any help would be appreciated!

[Pete M]

well, I can answer the first one, the 4banger got MPFI and OBD1 in 91 just like the 4.0.   :thumbsup:

[HOrnbrod]

Both the 91 and up 2.5 and 4.0 XJ/MJ models were MPFI OBD1 systems. The cross-body harnesses for the 4.0 and 2.5 have different part numbers; what the difference(s) are I don't know. I doubt if they are interchangeable. There were also subtle connector differences between the 91 and 92+ harnesses, so I'd try to find a 91 XJ/MJ cross-body harness at a yard to be sure they would all be PnP.

[JeepComanche89]

Both the 91 and up 2.5 and 4.0 XJ/MJ models were MPFI OBD1 systems. The cross-body harnesses for the 4.0 and 2.5 have different part numbers; what the difference(s) are I don't know. I doubt if they are interchangeable. There were also subtle connector differences between the 91 and 92+ harnesses, so I'd try to find a 91 XJ/MJ cross-body harness at a yard to be sure they would all be PnP.

Ok so I think I understand. Sounds like the 2.5 harness would not work for me. 

 

But as far as the XJ harnesses went I thought even if I got a 91 crossbody harness, it would not be plug and play into a MJ? I'm ok with eliminating wires for the rear, but its my understanding the fuel pump wiring is completely different. 

[HOrnbrod]

The crossbody harness is up front - has nothing to do with rear lighting. Download the 91-93 Parts catalog HERE. Look in the GROUP 8 Section, ELECTRICAL, WIRING for the MJ/XJ vehicles. This will show you how the wiring harnesses interconnect.

[JeepComanche89]

The crossbody harness is up front - has nothing to do with rear lighting. Download the 91-93 Parts catalog HERE. Look in the GROUP 8 Section, ELECTRICAL, WIRING for the MJ/XJ vehicles. This will show you how the wiring harnesses interconnect.

Awesome thank you, I am going to try and navigate it now