Before testing the water inlet switch,
unplug the refrigerator to avoid an electrical shock hazard.
There are two types of ice makers, those in which
all of the parts can be individually replaced and those in which
some of the parts are clustered together into a control module.
To determine which model you have remove the outer face plate.
If there is knob, pull it off first, then pry off the face plate
with a small screwdriver.
Modular units have holes in the module's face
plate for test probes. If you see several holes, each marked with
a letter, it is a modular unit, follow this link to view modular
instructions. Component units (like the one shown below) usually
have exposed gears and don't have holes for test probes.
Before testing the water inlet switch,
unplug the refrigerator to avoid an electrical shock hazard. 
