I've only ever run across two. One from the rear of the pass head to the firewall. The second one snapped off when I pulled the subframe out from under the body. It connects from the lower pass side of the firewall(near the access hole for the body bolt) and adjacent to the inside of the frame rail. Seems like I may have seen one attached to the steering box at some point but can't say it was original.
If I were to guess where a third one would be attached I would say from the rad support to the frame rail because your headlights ground to that. There was a third strap in the new package but I never figured out for sure where it was supposed to go.