Defogger won't work in 2009 Chrysler 300

Question

As winter is now here a functional defogger is a requirement yet this year my car won't defog no matter what I try.

All vents in the car are functional and blow whatever is pumped through them (eg I don't think there is a block of any kind, and both hot and cold work)

What I've noticed is that my model doesn't have a toggle for "recirculating" the air inside the car vs. pulling in fresh air.

Long story short the best I can do is full fan, set to defog, with the temperature on COLD. Although this keeps the windshield and driver/passenger windows mostly clear it isn't ideal when its freezing outside (I live near Toronto Canada, so it's a full 4 moths of winter)

These are the controls I have:

Is there a part of defog that should work like A/C that tries to remove humidity from the air?

Answer 1

The defrost setting (left most position on the right knob) should cycle the a/c and blow dried air onto the windshield. The a/c should dehumidify the air the result of which is less fog. The recirc function you are looking for is the two right most switch positions. This is not the selections you want for defogging. The humidity in the cabin will not be removed but recirculated. The most common causes for fogging issues are leaking heater cores, do you notice low coolant levels, a sweet smell when the fan is on, or an oily film on the windshield interior, all indicate a leaky heater core. Another cause is a leak that allows rain into the cabin. As it evaporates the humidity increases. If the heater box drain is plugged the moisture that the a/c unit removed from the air collects in the heater box and is recirculated resulting in fogging.