A/C problem

System cools with 18 degree splits. Runs for 10 hours and shuts down. Had some frayed signal wires outside and repaired. Same thing. In my opinion it runs that long to get area cooled down to thermostat setting then turns off. However it does not come back on when temp rises above temp setting. What is wrong? The 10 hours seems to be how long it takes to get interior down from 90 to 74.