what cause the heater and a/c panel not to swap from vent to defrost? on 2008 Ford Escape

it only blows from vents and only way the heater will blow warm air is if ur going down road. if it idiling it blows cold air

Asked by for the 2008 Ford Escape
That system is fully electronic and you need a scan tool for diagnostics. Have it checked at a shop and let us know what they find, include any trouble codes from the system if you can.
ok thanks