Sorry for the late response. Yes, they are magnetically controlled “lifters” (also known as dosers). When a current is applied, the magnetic inside the doser lifts up and ‘doses’ the syrup based on the size selected. One “shot” for a small glass, two “shots” (or lifts, if you will) for the medium size, and three “shots” for the largest size (~4 oz, ~6.5oz, ~10z).
Very simple, mechanically, so if you have one magnetic coil pack that isn’t working – how to test – swap a ‘good’ one into the ‘bad’ place… does the good one now stop functioning? If so, the wiring might be bad there. If the good one continues to work, it may be that the coil pack may be defective. Try it in the known good spot to confirm. If it’s failed, I can get you a refurbished/used one.