The more I think about it, the more I either doubt what I’m seeing on the pg 81 diagram. Or else I’m not understanding how that diagram works. I know from my own prior troubleshooting that there are separate fuses for LH and RH dipped beam headlights.

I just looked at my Haynes book wiring diagram, and if it’s at all accurate then the news is encouraging. It shows a single common power path through the CEM/relay/shunt etc and THEN runs to the engine compartment fuse panel where it FINALLY splits into separate RH and LH paths. So as I recall you said both fuses #17 and #18 are showing uninterrupted power flow. That would eliminate the switch, CEM, relay, shunt, as possible points of failure. As a confidence test you could try jumping straight from the fuse to the bulb to verify that everything upstream of the fuse is OK and that the failure is somewhere between the fuse and the headlight. Did you test for interrupted power at the headlight disconnect or at the bulb itself?
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