If I've got it right the super tweeters use a polymer film and have no real voice coil. This would make checking them with a DVM invalid. They probably work just fine.
From Wikipedia:
HPM stands for “High Polymer Molecular”, in reference to its then newly-developed high polymer molecular film supertweeter, a design that is used to convert electrical energy into sound to a degree that had previously only been theory. It is damped by elastic materials to prevent the deterioration of its best characteristics, and eliminates excessive harmonic distortion. It is housed in a plastic case, with the film (and grille) shaped semi-cylindrically in order to project the sound all 180 degrees around the front of the speaker. The HPM super-tweeter design has no dome, magnet, voice coils, or any moving parts at all.[2] The frequency response of this driver ranges up to 25 kHz, exceeding the capacity of the human ear.
