This is a good one. Recirculate

jagabom (Esquire) · January 14, 2016

I live in Canada but will use degrees F for this. 2015 Silverado 4.3 WT. Basic heater controls. I have noticed that as the temps get colder that the recirculate feature doesn't work at or below -4. When in vent or vent/floor mode the recirculate mode should work. Does not work in any other modes which is normal. Was doing some checking today. Above -4 the recirculate mode works. Below -4 the recirculate mode does not work. You can tell as the air noise is different in recirculate mode. I thought maybe the heater control was defective. I was driving around today and the temp was -4. The recirculate mode did not work. The temperature rose to -3 and the recirculate mode worked again. When the temp went to -4 the recirculate mode stopped working. Is something defective or did GM program the recirculate mode to not work at or below -4 due to the possibility of fogging the windows? Seems weird as below -4 you want recirculate mode to work as it is cold out. Hope it all makes sense.

Jim

15slvrDbl · January 14, 2016

If we get down that cold I'll have to check it out. I also use recirculation to not keep pulling in cold air when im trying to keep warm. We've only got down to 7 above so far.

akkrezz · January 14, 2016

Ill have to give this try. I live in Fairbanks, Ak where it is regularly below -20 in the winter. Right now we have a heat wave going on and its between 0 and 10.

redwngr · January 14, 2016

I live in Canada but will use degrees F for this. 2015 Silverado 4.3 WT. Basic heater controls. I have noticed that as the temps get colder that the recirculate feature doesn't work at or below -4. When in vent or vent/floor mode the recirculate mode should work. Does not work in any other modes which is normal. Was doing some checking today. Above -4 the recirculate mode works. Below -4 the recirculate mode does not work. You can tell as the air noise is different in recirculate mode. I thought maybe the heater control was defective. I was driving around today and the temp was -4. The recirculate mode did not work. The temperature rose to -3 and the recirculate mode worked again. When the temp went to -4 the recirculate mode stopped working. Is something defective or did GM program the recirculate mode to not work at or below -4 due to the possibility of fogging the windows? Seems weird as below -4 you want recirculate mode to work as it is cold out. Hope it all makes sense.

Jim

Do you have it working in deg C or F?

Clocked92 · January 14, 2016

Whenever I've run recirculate in the winter, my windows fog up really quickly. I'm betting GM programmed something in so this wouldn't happen.

FishinJ · January 14, 2016

I gearing up for our coldest day of the year next week. Suppose to get down in the mid 40's and might have to turn on the heated seats and steering wheel.

Jake56 · January 14, 2016

The weathernetwork had a article about what are the best settings to defog your windows in winter , and it clearly stated that the recirculate mode should not be used ........think of it this way the reason you have fog on inside window is humidity in the air inside the cab (slush and boots , wet fabric etc) ,.....meanwhile outside your vehicle in cold weather (eg below minus 4 ) the humidity outside is less than inside your cab where you are also breathing out moisture.......so recirculate is not recommended. You want to pull in less humid air form outside so you don't fog up. GM probably accounted for this.

chuckl1218 · January 14, 2016

I gearing up for our coldest day of the year next week. Suppose to get down in the mid 40's and might have to turn on the heated seats and steering wheel.

Your coldest day of the year and mine are a little different than the OP's...looking at 32 on Saturday

I can't even add here except to say remember that the heated steering wheel is manual, where heated seats can be set to be a part of remote start...

jagabom (Esquire) · January 14, 2016

Not sure what you mean redwngr. The trucks is in C. I just converted the numbers to F to make it easier for everyone. If that's what you mean. Just today I was driving with recirculating on. The temperature was about -3 or so. The temperature dropped to -4 and the recirculate door closed by itself. Funny thing is I don't remember the truck doing this last February when I bought it. Since then I got the heater reprogrammed as sometimes the fan would not turn off with the switch in the off position. I wonder if they slipped that change in then.

Jim

Victor Ferreira · January 15, 2016

How long were you driving?

I never use the recirculate button (I usually keep it on Auto) but a lot of modern vehicles automatically disable the recirculate function after a period of time, as to prevent large amounts of "used air" (CO2 rich) in the cabin.

Obviously I can't confirm this is the case because as stated, I don't use the function, and because the coldest it has been over here is 55.

jagabom (Esquire) · January 15, 2016

How long were you driving?

It can be 5 minutes or 15 minutes. Time doesn't seem to make a difference. Just the temperature.

Jim

redwngr · January 15, 2016

Not sure what you mean redwngr. The trucks is in C. I just converted the numbers to F to make it easier for everyone. If that's what you mean. Just today I was driving with recirculating on. The temperature was about -3 or so. The temperature dropped to -4 and the recirculate door closed by itself. Funny thing is I don't remember the truck doing this last February when I bought it. Since then I got the heater reprogrammed as sometimes the fan would not turn off with the switch in the off position. I wonder if they slipped that change in then.

Jim

The truck can be set to use/display either -- you didn't specify which you used, so that's why I asked.

Mine is also a Cdn truck, but I run mine in deg F almost all the time. I was still in school when metric was adopted so I can (and do) work in both sets of units -- just like to know which is being specified.

If weather cooperates, I'd see if mine has the same behaviour. Just wanting to know if I should check at -3F (-19C) or -3C (27F).

jagabom (Esquire) · January 15, 2016

For C the numbers were around -20 and -18 or so. That seemed to be the change over. I was 20 in 1975 when this whole metric thing was going on. I use only C for temperature but never converted to liters/100 kilometers. Still like miles per gallon. Strange. I am from Winnipeg.

Jim

redwngr · January 17, 2016

For C the numbers were around -20 and -18 or so. That seemed to be the change over. I was 20 in 1975 when this whole metric thing was going on. I use only C for temperature but never converted to liters/100 kilometers. Still like miles per gallon. Strange. I am from Winnipeg.

Jim

I use both temps, both speeds, and both distances.

Like you, L/100km just doesn't work for me.

I'm always amused that when you set a Canadian (GM) vehicle to 'inch' units it uses US gallons rather than the imperial gallons that were used in Canada prior to adoption of the metric system.

Victor Ferreira · January 18, 2016

On the unit note, I wish we could set the temperature unit separately from the distances. I grew up overseas and while now I sort of understand this whole Farenheit thing, this was not always the case.

For those of you who can't get used to L/100km, I'm also there. Km/L has always been a better unit in my opinion.

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