Do a search for EATC
Self Test. There are numerous posts in the forums depending on your model and year.
Climate Control Only Blowing Hot Air
Air Conditioner Blows Hot Air
Basically this does the following (copied from another post I found)
This test exercises all the vacuum switches and electric actuators, then it displays an error code for the malfunction if there is one in the ac display.
Unfortunately it is only for the Ford products with the digital climate control.
DIAGNOSIS AND TESTING (Continued)
• To enter the self-test, press the OFF and floor buttons simultaneously and then press the AUTO button within two seconds. The display will show
a dashed line in the center of the climate control display window of the integrated control panel (ICP).
• The test may run as long as 30 seconds. Record all DTCs displayed. The self-test is completed when 888 appears in the center of the climate
control display window of the ICP.
• To exit the self-test and retain all intermittent Air Temperature Powertrain DTCs, press the ‘‘—’’ (cooler) side of the TEMP Sensor Circuit Control/Emissions
button. The RCC module will exit the self-test High Diagnosis(PC/ED)and retain all intermittent DTCs.
• To exit the self-test and clear all DTCs, press the front defrost button. All RCC module DTCs will be cleared.
• Always exit the self-test before powering the system down (system turned off).