Alright guys so basically this is whats going on. I bought a Chasebays engine harness that just wouldnt work correctly. As a result I had to buy a used '03 evo 8 harness and swap them out.

So I have the whole harness in the car, and I know what all but one plug is. Its the longest lead on the interior side of the main engine harness. I cannot remember what it is for the life of me. I think it may be to the I/C sprayer switch but I'm unsure.

Can anyone confirm? Sorry for the pics.