I have a 2013 Optima SXL I had some issues with it overheating, I replaced the Thermostat, Temperature sensor, checked all the relays, All good. Car no longer overheats however, I noticed the High speed on the radiator fan is not kicking on? I ran a test and was able to kick the high speed on with the diagnostic computer so I know it's working. When the car is idling and the temp outside is 90+ degrees the air is off, the fan does not run. I wait to see if it will kick on but it never does. Car's not overheating, but no fan? When the air is on only the low speed runs. Any help to what I should look for?