Just cleaned the complete system, at furnace and outside. Had unit serviced (Sears Kenmore) for low freon, now when I turn on A/C the fan outside runs OK but the compressor kicks on then off after 10 seconds. This is the first time I ran the unit since it was serviced by a technician. Could this be a relay problem. The compressor won't stay on even though the line gets cold and hot air is blowing out from the fan. (the a/c guy said everything was running fine after he serviced it last week) Any suggestions, I hope it is not the compressor.

Vince

If the compressor is coming on and staying for 30 seconds or so and then cutting off and the air coming out the top of the unit is hot and the suction line is hot, my guess is that you have an over load of freon. Did the service man charge you for freon and if so how much?
The unit may have high and low pressure switches to protect the unit. Some do and some don't.
Another possibility could be a very dirty outside coil.

Rate this answer Please.

I would hope the service guy would have checked and cleaned the condenser coil while he was there. Does the condenser fan seem to be running at full speed? If so, I would have to agree that you either 1. have an overcharged system or 2. the freon has leaked out and the compressor is going out on low pressure. I would contact the service guy that checked the system ASAP to resolve this problem for this may be something he did, I would advise you to shut the system off until it's checked out or you may damage the compressor.