Started having a problem a couple of days ago where A/C cold air stops coming out of front dash vents and switches over to defroster vents intermittently. Air is cold coming out of defroster vents until it switches back to dash vents by itself. Seems to be doing this every 2 to 5 mins. Anyone ever seen this happen before? If yes, what was the fix? TIA...

 

Good news is that you don't have a 'blend door' problem. Sounds more like a vacuum problem. Do you here any hissing sound under the dash? Take the black cover off thats under the dash and over the tranny hump for better acess. Another place to look is, check the black hose that runs between the battery and the firewall. This hose is a very common failure problem.

 

Thanks for the reply back. I'm not hearing any hissing inside. I'll look for the hose under the hood you metioned.

 

I just picked up an 02 Screw with 42K on it. I went to the mountains last week and going up the hills the AC would stop coming out of the vents and start coming out the defroster. Air would still be cold though. This happened everytime I gave it gas to get up the hill. It works fine around town though. Anyone know what the problem could be? Thanks

 

Happy ending for me. I ended up having 1000 miles left on Ford 6 yr 75K ESP extended warranty. Here's what the dealer service department diagnosed and fixed. Cause: Vacuum Leak in EATC (Electronic Automatic Temperature Control) AC Blows out defrost. Performed EATC self test no codes. Performed vacuum leak test and found vacuum leak in EATC. Dealer replaced EATC control head (A/C control panel beneath the radio) and retested Ok. They replaced part# '2L3Z*19980*AA'. Service Manager said this part was approximatley $500. Hope this helps you with your problem.

 

Similar issue. The EATC would be off and all the sudden I would get hot air out of the lower vent by the gas pedal. I had to turn on the auto then shut off. 10 miles later the same thing. Dealer replaced EATC control head. Thank god for the Ext Warranty!

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