AC blows cold for approx. 20 minutes than gets warm. I have read other post and possible reasons:compressor bad, temp. gauge sensor, pressure cycling switch, cut out switch. Is the temp. reading of the outside air connected to the temp. gauge sensor? The temp readings sometimes is 110-140 when the real outside temp is 90-95. So, if the reading is 120, can the sensor cut off compressor? Were are the pressure cycling switch and cut out switch?

Thanks