Long story short, I have two very rough 91 MJ's. One is a 2.5L HO and the other is a 4.0L HO. My goal is to build one good truck with a 4.0L HO. Both trucks are HO and have the Chrysler fuel injection system.

My question is, will the 4.0L HO engine bay wiring harness mate up to the 2.5L HO dash harness? The plugs at the firewall are the same shape/size, but I am unable to find plug pin outs for the harnesses in the FSM to confirm. I do realize the 2.5 tach might not work correctly with the 4.0.

I am trying to see if I can avoid swapping the dash/dash harness.

Thanks for the help!