AC compressor only will work after car reaches operating temperature and the radiator fans come on. Normal ac at that point. Before that point. Ac compressor won't stay on.

Have you had the pressure checked in the system with a manifold gauge to make sure there is the correct amount of freon in system?

You might have a faulty coolant temp. sensor. This sensor can be checked with a Digital Volt/Ohm meter. You will need the factory Temp/Ohms relationship chart for this vehicle. If a faulty ETS tells the computer the engine is cold.....the computer will not allow the AC to function until the engine warms up.