joeny1980

This is weird - I've always noticed that on my 2007 tC that when I turn on the defroster the recirculation button/light will automatically turn off - this is a great feature b/c most people dont even realize that this is the right way to defrost a windshield (letting in fresh air). Anyhow... one thing that made me notice this feature is that my girlfriend who has an '06 tC - her car does not do that.

Well, I just had some repairs done at the dealer. Inspection, brake work, and fixed my floppy visor (under warranty). Driving home I noticed that my defroster wasnt working the same way. It doesnt make sense based on the repairs done. Maybe they hooked into the computer for the inspection and flashed it or something. Its an odd random feature to just disappear. It could just be a coincidence.

Anyone have any thoughts. I think if I ask them they will be clueless and think I'm nuts for even caring.

Sciontistical_One

iTrader: (2)

Take it back... what you're saying is the correct way that it should work... and they should fix it, regardless of how petty that it may seem to them.

locondcoco

just to cover all the bases before you go back. are you sure you have it ONLY on the defroster? cuz if you have the blower set on the feet AND defroster, it wont automatically go to recirculate.

engifineer

Correct, you can still turn the recirc back on and it will stay if the feet and windshield selection is selected.

If you chose the actual defroster button, it will take a second, and then the recirc will turn off and you cant turn it back on until you take it out of defrost mode.

joeny1980

Yeah its definitely only the defroster. I cycled thru them. I was thinking MAYBE it had to do with the temperature outside , its in the teens here - but I know i would have noticed this last year. Actually, locondcoco - I'm from Long Island also - yours working right?

Does anyone know if there would be a reason they would do anything with the computer for the type of repairs I had.

engifineer

There is only two choices to cycle through, defroster on and off. I say this cause it sounds like you are cycling through the vent settings (vent, feet, windshield, etc), which will allow you to run the recirc.

The one that wont let you run recirc is the actual button under the mode button ( and above the rear defrost) for the defroster. Is this the one you are using?

sciontc_mich

Actually hitting that function when cycling through the modes will turn recirculation off, but I think that if you push recirc again it will go on.

the button for front defroster above the rear defroster button will NOT allow you to turn recirc on at all.

Sounds like your 07 is working correctly, it should go fresh air when you go that mode. if yours isn't doing that after the dealer worked on it, make them know they did something. i can't see how they would've programmed that. I mean I didn't know you could reprogram that chip inside the hvac controls.

I'm wondering (not defending the dealer) if since you have an 07 if you don't have a defective HVAC controls. They had updated the circuit board on the 07's and had a bad batch.

joeny1980

Thanks for the explanation but I promise you its not me. I'm actually very familiar with how it works - thats why I noticed it was working differently right away. Like I said my gf has an 06 and hers works slightly different (it does not AUTOMATICALLY turn off the recirculate when the windshield-only defroster is on). Mine is acting just as hers does now.

I was hoping someone was familiar enough to know if there is any reason they would be flashing my computer or anything like that.

sciontc_mich

a friend of mine, his tC just started doing that today too! It used to automatically revert to fresh air if it was in recirculation when the front defroster button was pushed. Now it just stays in the recirculation mode and you have to manually press the button to go to fresh air.

Seems that you're not alone in this malfunction! and at the same time, wow.

SquallLHeart

hmm.. i've never seen that type of problem before...

i've always seen the electronics on the hvac board to always turn off recirc when defrosting..

time for a dealership trip looks like..

sciontc_mich

sqaullheart- yeah exactly but then all of a sudden i noticed it wasn't working in his tC.. i was like, oh i've heard of this before. and here's the thread (we're in it).

So i'm thinking it's probably the a/c control assembly that's bad. since that's the brains that controls the modes, nothing else. Would I be correct?

SquallLHeart

i believe the brains is in the hvac board itself...

could try switching it out with another one to test and see (if you have a spare one...)

well.. you can take yours out and test it in his car.. that would do it..

sciontc_mich

yeah thanks squallheart, you helped me prove that yeah it's the brains (the board). was looking at the wiring diagrams and that is what i concluded, thanks for the help.