I infer you were just connecting the test light terminals across pairs of connector terminals to get those results?

The better approach to distinguish the hot wire from ground is to connect one terminal of the test light (the alligator clip, if it has one) to a known ground, then touch the other terminal probe to each of the connector terminals to determine which one is getting power with the switch in each position. To confirm which one is the ground, connect the clip to the battery (+) then touch the probe to your probable-ground terminal in the connector, which should then light it up.

Anyway, your diagram does look typical for a 5x7" rectangular combo-beam (H6054 type) where, looking at the connector end, the right terminal is a ground, the top terminal gets +12VDC when the low-beams are on, and the left terminal gets +12VDC when the high-beams are on.