May seem like a bizarre need, but I need to modify my heater such that I can use the windshield defroster while still set on internal air recirculation. Everytime the defroster is chosen it automatically switches to external air and can't be changed back.

Anyone done anything like this or have any ideas?

Thanks in advance!

 

It won't work as well as you will being throwing more humid air at the windshield.

 

Understood, but I still need to do it

Any tips are appreciated!

 

Why do you NEED to do it, as you have stated?

 

Uh, why? You do understand that by setting this up, your vents will actually CAUSE your windows to fog up, right?

Its really not what you think.

 

Or are you trying to use the COBB tuner?

 

I was wondering the same OP's question. I put the defroster on recycle in my old corolla so the car will warm up quicker. They don't fog up if I am not in the car usually.

 

We have terrible frost problems here, but the answer is not recirc -

When it's minus 30* here and you put it on re-circ it will fog up/ice up and you're screwed.

Interesting fact - the difference between inside air and outside air is less than 2 degrees at the vent outlets, even with 40 or 50 degrees difference in outside temp..... Put a thermometer in the vent and swing between the two settings if you need proof.

What 'just makes sense' ain't always true.

S

 

Won't the engine heat up faster though?
Up here where it is dry, I don't have problems with recirc on the windshield if I am not driving it. I put the vents to recirc when warming up the car. I notice that the engine warms up faster and there is no fogging up.