PLEASE HELP !!!! New to the forum. I have a 2004 Mercury G/M. The automatic climate control blows air from the DEF vents, then floor vents, then dash vents, and then back again. This happens with AUTO setting, MAX A/C, NORM A/C, or VENT. What the heck is going on ????

is it an electronic control with buttons or do you have knobs that turn the climate control?

hey there, yes it has push button. Full automatic climate control.

Try the self-test: press OFF and FLOOR buttons simultaneously and then press the AUTOMATIC button within 2 seocnds. This will display any trouble code(s)
Exit self-test and clear codes: press the DEFROST button.

Cue ball, Follow what duffy said above. Ths is the information I was looking up for you. let me know if this worked.

Thank you gentlemen, I will try this test as soon as my wife gets the car home!!. I will tell you the results soon after. Thank you !!!!!!!!

Thanks for the info. I tried this, the little green bar went into search mode, but pulled no trouble code. The screen went to 888 with all other lights on . However, no change in system. I even tried pulling battery cable off, left it off for some time, then attached to see if I could clear any trouble codes. The result, nothing. Still have same problem. Does this indicate a vacuum problem somewhere????

Yes, this may point to a vacuum issue somewhere. The book says look at these items: Vacuum hoses kinked/pinched, No vacuum to the a/c control, Airflow door stuck, Vacuum control motors, a/c vacuum reservoir tank, a/c vacuum check valve. In other words, check all vacuum line and motors.

you might have to pull the fuse to the ac or heat controls when you disconnect the battery to reset the code. this should be left off for 15 minutes. the computer has a 15 minute back up powerwhen the fuse is removed. the other way is to have a scan tool reset it if this does not work.

Thanks Jason, I will give it a try! I really want to thank everybody for all your help with this problem.