DIY - Rebuilding the headlight switch ↗
Kitchen-table rebuild of the expensive E9 light switch: pry open the crimped aluminium case, note the contact layout, mind the eight springs, clean and sand the contacts and rheostat, re-grease and re-crimp.
Tools mentioned: Small screwdrivers, fine sandpaper, contact cleaner/lube
Our part is also listed for E24; the switch internals may differ.