It was 30 degrees last night and my wife and I had an exciting drive home for two hours. She drove and I wiped windshield down every 3 minutes so we could get home at 2:00 am.

I replaced heater core for the second time a few months ago on our 2003 S with auto climate control. Don't think that could be gone again.

Couldn't get hot air to stop coming from defrost vents, even with unit off. We did have plenty of heat. I didn't see any coolant leakage from heater core area as I did before. Smelled a bit of coolant regardless.

Is there a outside air flap that could be broken which keeps system in recirc mode, thus fogging up windows? I had an old audi that had a flap spring which broke and that fixed it.

I am going to try to run the control diagnostics but didn't see this similar problem in any searches.

Thanks

 

I would go back in and make sure that the heatercore is seated very firmly against the firewall and there is no condensation on the pipes. That is the first thing that comes to mind. I hope this helps.

 

Will do.

I ran the diagnostics and the following results:

On mode 1 - get a FF 00
On mode 2 - get CA then CC
On mode 3 - all controls work manually fine. Fan and flaps all direct air to the correct locations. recirc works fine and I notice airflow changes accordingly.

other thoughts

mike