If you would do a search here, you would find AT LEAST 100 posts describing your situation.

There is a low pressure switch that interrupts the clutch circuit when the refrigerant pressure is low. This is to protect the compressor from a low refrigerant situation because lubricant is not circulated through the compressor under this condition.

The first thing that should be done in almost all a/c diagnostic cases is to hook up the manifold gauges and check the pressures.

Good luck,