Have an 2013 Elantra GLS with an AC issue. When parked or stopped and idling AC works like normal, cold air. When driving below 40mph AC works intermittently (more off than on), cold air...then outside temp air (recirculation not on) or internal air temp (recirculation on). Above 40mph nothing at all. May come on if AC button is turned off for 3 seconds then turned back on. Seems as if AC turns on (or blows cold air) when radiator cooling fan kicks on. Hard to diagnose since at idle works fine. Replaced expansion valve. Refrigerant is at spec. Looking at replacing pressure sensor. Then compressor. Not sure what to try next. Any suggestions?