The car came with the low-beam headlight fuses wired to a live fuse, so that works. With the wire on the fuses the high beam (forward and locked on the comboswitch) does not work, but pulling all the way back on the comboswitch (flash-to-pass) works.

Pulling the wire off kills the low-beams. Since turn signals were intermittent it made sense to replace the comboswitch, but followed advice on this forum to first just plug new comboswitch in and test before removal of steering wheel. Had the same problems with the new comboswitch.

I'm going to re-test the new comboswitch though; just in case I missed something.

There's part of me that says it is a relay; too often in working with different forms of electronics there is usually a relay, or capacitor or transformer that has died or is dying causing the problems.