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Discussion Starter · #1 ·
I had a bad experience today with the Volt failing to defog the windows, and I was wondering if this is typical, or unusual, or if maybe I was using the wrong climate setting settings?

When I got in my Volt to leave work earlier tonight (temp was ~28F), all of my windows were fogged up pretty badly. So I immediately turned on the windshield defroster. I could hardly see out of any of the windows, and wiping the condensation away did virtually no good, so I just sat there waiting for the fog to clear from the windows.

After a couple minutes with no improvement, I noticed that the heat was on but the A/C was not. Since all of the windows were seriously fogged up and the air clearly needed dehumifying, I thought this was strange. So I tried changing climate settings to see if it made a difference. I tried turning on/off Auto Defog. I tried turning up/down the target temperature. I tried Fan Only, Eco, Comfort. Nothing worked in getting the A/C to turn on. It ended up taking maybe 6-7 for the windshield to clear up sufficiently for me to see through the windshield and drive away, and even then there was still a lot of fog around the edges of the windows.

I left defrost on for the duration of the trip. By the time I got home, the A/C had still never turned on, there was still a small bit of fog around the edges of the windshield, and I had used 3 kwh's to go 4 miles. :(

Is this normal? I could've sworn that in the past A/C would come on automatically when I turned on the defroster with my windows even slightly fogged. Is there anyway to force the A/C to turn on?
 

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Same fog here as in Aurora. The Defrost button did the trick, then fan on low. Maybe your defroster is not working?
 

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I think the biggest issue with the defog button is it won't change the fan speed. if the fan is set to the lowest setting, it won't speed up for defog.

I've gotten in the habit of pressing Auto then Defog, that way the fan speed usually ramps up to maximum.
 

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The front defrost works quickly on my 2011. Being in "Auto" mode first helps, as does raising the temperature. A/C and electric heat both will run, except at very low temperatures where only the heat runs.

You may want to have the dealer check out your HVAC system.

GSP
 

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Similar situation in Michigan with the rapidly dropping temperatures - my windows fogged up badly after parking for a couple of hours, but defog cleared them up fairly rapidly. I did have to manually turn up the fan speed, where I normally run in Auto / comfort. I did notice I had it in ECO prior to parking to extend my range in mild temperatures, later turned colder. This probably had helped me by running the A/C compressor less, or not at all.

I believe the difference is that the compressor ran for me (not sure of that) because it was not yet down to freezing here. The transitions are tough because you have all the moisture in the A/C evaporator, then the compressor will not run when the temperature drops. I don't know the Volt's control calibration specifically, but I worked at GM for over 40 years, including at Frigidaire when we made A/C compressors for GM, and at a certain point, on any vehicle, the compressor is disabled when it gets cold enough to protect it (and the evaporator would freeze up anyway).

You might try opening the windows to let in fresh air. If you have chronic fogging problems, have the recirculation door checked (you do not want recirc during defog or fogging conditions). The Volt's humidity sensor and automatic recirc help (assuming you have it set to auto defog and auto settings), but it is more sensitive to fogging under changing conditions than other vehicles I've driven, including my GMC Yukon XL Denali.
 

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My windshield defogger works great. There are two defrosted buttons on the center stack, the one on the right is for the windshield and the one on the left is for the rear window. I know I selected the wrong button once or twice right after I bought my Volt.

But in any event as soon as you press the right defrost button you should hear the fan ramp up, air flowing from the top dash vent and the heater ICON switch from OFF to ON.

I needed it this am on the way to work and a few minutes was all I needed to clear the windshield and drivers door window that had fogged over. That's what getting into a cold car with damp hair from over sleeping and running late.
 

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I run mine in Auto Eco all the time. Last night I too have heavily fogged windows. I pushed the defrost but, both front and rear and all my windows were good in a couple minutes. This was after the car sat outside for an hour. Defrost setting for the front window always increases my fan speed a lot. MY 2013.
 

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Discussion Starter · #10 ·
Thanks for all the replies.

No insult about your intelligence is intended, but did you press the button to defrost the front or rear windshield?
:rolleyes:

Did you have the system set on recirculate? That keeps any humidity in the car and you generally don't want that.
I had it on auto-recirculate. I did think about turning that off, but I left it on auto-recirculate to see if the car could "figure it out" on its own and either turn on the A/C or bring in outside air without me interfering. In the future when I'm not testing the car's "intelligence", I'll be sure to turn it off.

The front defrost works quickly on my 2011. Being in "Auto" mode first helps
I did not try "Auto". I'll give that a try next time.

I don't know the Volt's control calibration specifically, but I worked at GM for over 40 years, including at Frigidaire when we made A/C compressors for GM, and at a certain point, on any vehicle, the compressor is disabled when it gets cold enough to protect it (and the evaporator would freeze up anyway).
I did not realize this. Could this be the root cause of the A/C staying off then?
 

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jsmay311: I had to use the defog once, and it took a bit for me to figure out which was the front or rear, hence I asked :)

I always have my car in Eco/Auto, and while I've only used the defog once, it also jumped up the fan speed.
 
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You can always call your Volt Advisor as well! If it continues to fog up on you I would recommend to have your dealer look at the humidity sensor in the cabin.

-Ian Chevrolet Volt Customer Service
 

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No insult about your intelligence is intended, but did you press the button to defrost the front or rear windshield?
ha ha, I keep forgetting which is which!!! the "square" one on the left of the button row, or the "trapezoid" one on the right of the button row? now I think the left/square one is the one for the forward/front windshield, yes? but I won't know for sure until I actually have to use it (I've only used it maybe once or twice since I got my 2013 back in October)
 

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From the touchscreen, I select the vent/floor setting, 5 fan speed, ECO, 70 degs and it usually keeps the windshield and front windows from fogging. I crack a window and that keeps the rear hatch from fogging up. Just play around until you find the right combination that works for you.
 
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