ignition switch ???

If the brown is still hooked up to the ballast it will get some feedback in "run." If the engine bay end of the brown is unhooked, should be zero

You want to make these measurements "loaded." If you have a heater, turn that on for the accessory reading. For the "run" reading make sure the underhood end of the "run" wire is hooked up. That will show up voltage drop problems

There has been threads on here in the past, sometimes when those switches go bad the internal parts can "dance" around in there and give you weird readings