I read that the subie harness is chassis and engine combined into one harness. So If I bought a version 1 front clip and was planning to put it in a 93-94 front clip, would I have to use any part of the US harness? Id have the ecu harness engine transmission from the donor car and I was thinking I might have to extend the harness because its RHD not LHD but Im hoping I wont have to start hacking up two harness and combining them to get it to work. Just trying to do my homework before I go buy this clip.

on the JDM harnisses the engine is not intergrated into the body like the USDM cars. when the clip is cut, you can still start and run the engine like everything is still a whole car.

as for longer wires. i would just find a new location for the ECM.

i just did a 96 JDM swap into an 88 GL wagon, and i put the ECM under the dash on the drivers side. without cutting any wires.

-=Suberdave=-

you don't have to extend ALL of hte wires just some... the older subies I believe the engine and body are 2 different harnesses. I bought a front clip... its the right way to go

But I will still have to integrate the jdm harness into my US harness correct? Or more like integrate the US harness into the jdm harness since ill be using the jdm ecu.

i guess i've never really understood why you cant just pull out the stock car's engine harness (or leave it in and unplugged for that matter) , put the jdm motor in, and wire the jdm engine harness to the jdm ecu ( and find a nice home for the ecu under the hood to make things even easier). i would imagine that the only things that you would have to wire into the car itself would be input for the coolant temp, tach, and oil pressure (all of which you could do without). you could wire in the few things from the car's harness that you might need (like the power steering pressure sensor). since jdm cars dont do emissions crap and niether does iowa i could just rid myself of all the stuff present on the car. i know that there is prob a million holes with this, but im just a noob really.

the first swap i did was just that. we removed the complete usdm harness, and then put the JDM RHD harness into the LHD car. we fit in teh mechanical bits, and fit the harness per JDM diagram. then the job was to extend the stuff to reach - i.e. dash harness on the proper side, fuesbox not on your foot, ecu to the Airbag placement, etc etc.

its not bad. just takes some patience and alot of soldering.

But its bound to be easier than hacking up 2 harness and combining them right?

perhaps. perhaps not. but i think it is.

The guys that did the wiring for my v2 swap had to combine the harnesses.

I did my 94 wagon to 97 JDM and it was not bad once I got the pinning of the ecu and the diagrams for both cars. You definately want to combine the harnesses. The 94 actually had 2 harnesses one for the engine and the other for the rest of the car.
So you really only need to hack the engine harness of the USDM car and then
tie in the misc items (temp, tach, Speed sensor (very important), etc) from the ecu to the other loom in the car. All and all about 17 wires.