I'm assuming it's on the Euro 300D.

Check your manual. Normal may have been 0 or 1. It's mostly to lower your low beams when the trunk is loaded and the nose shifts upwards so your headlights are on road and not the trees or oncoming drivers.

I think it defaults to full dip with no vacuum and the vacuum pulls the reflectors up. If your headlights were aimed with the engine off, it's possible they no longer have the range of motion to pull anything upwards since that's been dialed out of them.

If there's no vacuum line to the switch or to your headlights then it won't do anything.