Hi all, wondering if anyone might have some insight into an issue I'm trying to solve. If I depress the light button to the 2nd setting, I get no low beams. If i turn on the high beams, all 4 lamps light up.

I've checked the voltage at both the relay, and the fuse, for the low beams. they both throw to +12V on a voltmeter when the button is fully depressed. So I have to assume the disconnect is somewhere between the fuse, and the lamps. Any ideas about how to go about sussing the fault? Thanks! You guys are super helpful here!