E350 XLT 2014 Front AC works on High only

[GNX500 0]

Front AC runs on high only, Rear AC has no issues. I have replaced these components twice with genuine Motorcraft Parts.  Blower Motor Resistor, Switch on the Dashboard, and Blower Motor Relay. I have also checked the connectors on the switch for melting, burnt, corrosion, etc and have also checked for this on the Resistor End. Wires look good. AC blows cold.