Driver's and passenger's side vent temperatures vary by more than 11°C (20°F) (Climate Control)

Diagnostic Procedure 

Probable causes: The recirculation control door or the air mix doors are malfunctioning

Do the following troubleshooting:

• Recirculation control motor test 
• Driver's air mix control motor test - Refer to: Passenger's Air Mix Control Motor Test Air Mix Control Motor Test 
• Passenger's air mix control motor test - Refer to: Passenger's Air Mix Control Motor Test Air Mix Control Motor Test 

Also Check for 

• Climate control DTCs - Refer to: How to Troubleshoot the Body ElectricalHow to Troubleshoot the Climate Control System 
• Poor or loose connections at the terminals