I am not sure on this one, but I doubt you would need to drill in order to pull this through an existing hole. How big of a connector are we talking here?

It would make sense to use a hole near the steering column. This would either be the oval hole that is used for the clutch cable (MT) or plugged (AT) OR the round hole just below and to the right of the brake booster where the speedo cable passes through.

The factory probably had it pinned to the fuse block/bulkhead connector originally so no extra hole but I could be wrong.