I'm not aware of any wiring that isn't fused in one of the fuse boxes. Unless something was added into either and that should look like it's been added.
How about this.... I believe that there are three big connectors in the back of the underhood fuse box. If you removed one at a time and watched for the draw, you could begin to slim down the possibilities. And someone should have a listing of what is in the connector that ends up with the draw in it. That way we can help you start to pinpoint the issue.
