Which Relay is Which?, Highbeams won't switch Options

[ThinAir]

This is a 73, 2.0L. After changing the electrical part of my ignition switch, I think I must have shorted something because I've got a strange high/low beam behavior.

When I turn on the headlights they are on highbeam. I try to switch them using the stick, but nothing happens - no click or anything. I suspect that I blew the highbeam relay.

So, which relay is which? I searched and found a topic that says the highbeam relay is the silver square one on the top of the fusebox. Is this correct? If so, would this part at Pelican be the replacement? 141-951-253-B-M5206

I can find lots of resources that identify which fuse goes with what, but I can't find anything for the relays on the top of the fusebox. I have 3 round ones in a row, then the square one, and an empty round one above that. What do they go to?

Here's a rough diagram, looking from the top of the fusebox as if sitting in the driver's seat:

O - Empty round relay
O O O [] - Square, silver relay
| | |
--------------------------------- 3 Round relays

So what do these go to? The picture in my Haynes manual doesn't have the empty round socket and it thinks one of the 3 round relay spots is used by a buzzer, so I doubt that it applies at all.