A/C compressor clutch engages cyclically - no cold air

That is a normal cycle for a compressor. Have your refrigerent level checked to make sure you have enough to operate the system effectively. You might have a leak or it may just be low.

Thank you for responding. I understand that the clutch cycles on and off under normal conditions. I did have the levels checked, the system was evacuated and refilled. The mechanic used the three gauges to verify the pressure, etc. The problem still exists. If it were a normal situation, considering the refrigerant level is ok, I would get cold air but I am not. The car is only four years old and one year we had a cold summer so the AC was hardly used at all. For it's age and the amount of use I find it hard to believe that the compressor is bad. Is is possible that the clutch is the issue? When I first purchased the vehicle in 2011, it was new and when I shut the car off after running the AC there was a whistling sound. I brought it back to the dealer and they said it was normal, some valve on the firewall or something like that. I don't want to go through the expense of replacing the compressor if that is not the problem.