That loom only contains the pneumatic line for the trunk lock, and the wiring for the 3rd brake light... On N/A cars, it would also contain the wiring for the spoiler.

Double check the "snugness" of that seal... that's most likely the culprit.

Also, pull your trim panels and make SURE that no water is standing in the rear floor anywhere. The main "hub" for all locking systems is in the low-spot, near the gas filler tube (RH rear). When it shorts out, the car goes nuts and won't lock/unlock.