I have a AC unit when turned on it runs great cold air fan operates normal after about 5 min the fan shuts off . The outside compressor runs . No fan in auto or on? Can the fan relay be intermittent ?

Sounds to me like the fan is overheating and shutting off on its internal protection... maybe an air flow issue. Have you changed your filter lately? Or maybe your indoor coil is dirty. Or fan is starting to have issues with its winding or preparing to die.