Originally Posted by Okita Souji
Yes, it's the one by the battery with the brown and black plugs. Both are missing.
That sucks man! You can look into this harness, which promises to add the missing wires, so you can use your USDM engine harness. Supposedly it's for motors that didn't come with a complete harness...
... it is different from their AVCS bulkhead wiring kit, which most people need to wire up their ECUs.