From my diagram in Haynes,

With ignition "on" or "off", there should be 12 volts at the brown wire going into the hi/low switch on the stalk. This is provided by the brown wire (terminal 31b) located on the "step relay" mounted on the rail on fender wall, behind the battery.

Operating the hi/lo switch provides a path-to-ground for that 12V, which activates the step relay. (Path-to-ground is via the ground scrw I mentioned in my previous post.) One thing that happens at this point is that the blue hi-beam indicator lights up on the dash, as long as the stalk is pulled back. Actually, this last item SHOULD happen even with the ignition off!

If you get the blue light on dash but the headlights don't change, then the step relay is bad. Because part of it is working to illuminate the blue indicator, but the rest of it is not working, to change your headlights.

If you don't get the blue light, your problem still could be in the relay, the switch, or the wiring. A voltmeter will help to tell you.

Happy testing.

Hope you're looking at this. There's a fair bit of writing on this thread, let us know how it's going.
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Sven: '89 245, IPD sways, electric rad. fan conversion, 28+ mpg - auto tranny. 850 mi/week commute. '89 245 #2 (wifemobile). '90 244 (spare, runs).