Did you check the switch with for continuity? It has to show closed.

The power through it operates the relay coil that operates the clutch with it heavier contacts.

Not that you asked but I see a lot of questions about the filling or low side port location.

The reasons you should look for it where!

The port is always on the largest line of the system.

This line is always largest because the refrigerant is returning as a low pressure hot gas from the cars interior or cabin evaporator. Therefore, the volume has increased because it has picked up heat when it expanded in the evaporator.

Another reason for a larger line is because:

Since the pressure is kept lower due to the metering device It makes the pressure difference by adjusting the quantity of liquid released.

Less pressure less pushing force.

So the size of the line is increased to reduce suction drag. This keeps velocity up so that any migrating oil in the refrigerant will be returned to the compressor. The principle will not allow an oil blockage to occur in the evaporator bends and lowest spots.

Phil