Congratulations, you finally found my blog and I hope it will fix your problem with your Chrysler 300 fogging up. I had this problem for an incredible 2.5 years. I brought the car to three car garages, two of them are “certified Chrysler service centers”.
It turns out, when it comes to troubleshooting windows fogging up, their Chrysler certification was useless.
Meanwhile, it was really frustrating to drive in the car. Unless the AC was switched on, the windows would fog up within minutes, even though the engine was warm. So I went through a bunch of checks until I finally found the cause, by lucky accident:
Make sure the condensate drain isn’t clogged. Guess what, both Chrysler garages couldn’t find it and tell me where it actually is. But through careful observation in the summer I noticed there is condensate dripping, but by far not as much as with other vehicles, considering that our summers are very hot and humid.
Next suspect: the engine coolant might be leaking. This was a scary thought. However, the odor coming from the vents wasn’t the typical ‘sweet’ smell of coolant liquid. Also, the fogging only occurred in cold weather. I was told if the coolant is leaking, apart from the odor you would also see the coolant level drop eventually and the condensate on the window would be sticky. Mine wasn’t so that possibility was off the list.
A clogged air conditioner filter perhaps? That one would be too easy. I had changed filters often….
Then one day it occurred to me. I removed the glove box to check out the blower motor. I turned it on max and noticed it was pulling in cabin air. I went outside and held my hand over the intake and there you have it: there was almost no air being pulled in from outside!
The AC was on permanent recirculation. The door was closed and almost no fresh air was coming in. The cause of 2.5 years of suffering and “low-oxygen driving” was that the actuator was defect and the door over the blower was always shut, not letting much air in.
The odor developed due to mildew growing inside the AC system, because the air was too moist.
And it clicked in my head: that’s the reason why the AC switches on automatically when you turn the knob to recirculate air. The AC removes the moisture and prevents are moisture buildup inside the AC system as well as inside the car.
Because almost no fresh air was coming in in the summer, the AC condensate didn’t drip much, which now is logical because the only moisture the AC could remove is that from our bodies. Once you pull in hot humid summer air from outside, the AC is under a much greater load and hence creates a lot more condensate that is visible under the car when you stop at a traffic light.
The quick fix
The quick fix is to remove the glove box and unplug the AC recirculation door actuator. Then use a long screw to move the door down and turn the screw to hold it in place, so that it always stays open. Turn on the blower on max and check outside that lots of air is being pulled in. With wet hands on the blower cover, check that there should be almost no air being pulled in from inside the vehicle.
Here’s a helpful video that shows how to access the recirculation actuator and blower motor:
The real fix
The correct fix is to replace the actuator.
The part number is 68033337AA and you will find lots of matching parts on ebay.
Before ordering the part I would use a voltmeter to check the connection to the actuator and that it actually receives the electric signal, to rule out electric issues. The guy in the video above actually had a mechanic problem with the door itself, but either way, if you ask me, I don’t see a point in the recirculation mode anyways. A simple screw did the trick.
Fixing the odor issue
Walmart sells a spray you can use to spray into the air intake (with the filter removed) and the blower running on max. It disinfects well and the odor and scent of that spray will fade within days. As long as fresh air is pulled in, no mildew can grow, especially in the winter when the air is really dry. Another spray you can use is Lysol. They have one for the “baby room” with minimal scent at Staples.
I hope this post saves you money, time, and trouble.
Please feel free to comment below and share your story and whether you found alternative fixes / issues with your Chrysler 300.