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Auto HVAC Function


i20sailor

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Got my car last October in Michgan and the weather is finally getting warm again. I have my Auto Temp set to 66F and with the cabin way above 80F, the system will only have the fan at about 50% without any re-circ. I have to manually requet Max A/C for the cabin to cool down. Then, when I return to Auto A/C, the temp is set to "LO" and I have to manually re-set my temp.

 

Does my car have another software problem or is the system set up to work this way?

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Got my car last October in Michgan and the weather is finally getting warm again. I have my Auto Temp set to 66F and with the cabin way above 80F, the system will only have the fan at about 50% without any re-circ. I have to manually requet Max A/C for the cabin to cool down. Then, when I return to Auto A/C, the temp is set to "LO" and I have to manually re-set my temp.

 

Does my car have another software problem or is the system set up to work this way?

 

That sounds about right. Are you leaving the vista roof shade open? The system uses outside temperature in it's programming, and we haven't been too hot outside yet, so it's never going to ramp up to full fan until it's over 90 outside. But sometimes leaving the roof shades open is enough to get the cabin a little hotter than the system thinks it should be.

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That sounds about right. Are you leaving the vista roof shade open? The system uses outside temperature in it's programming, and we haven't been too hot outside yet, so it's never going to ramp up to full fan until it's over 90 outside. But sometimes leaving the roof shades open is enough to get the cabin a little hotter than the system thinks it should be.

 

Just another screw-up on Ford's part I guess! Why on earth would they not use cabin temp to control cabin temp? Outside temp can be an input, but ultimately the two are not related. I've never had a car that anoyed me so much on a daily basis.

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Just another screw-up on Ford's part I guess! Why on earth would they not use cabin temp to control cabin temp? Outside temp can be an input, but ultimately the two are not related. I've never had a car that anoyed me so much on a daily basis.

 

It does use both, but it uses the outside temp to gauge how much heating or cooling is necessary. 60 is MAX A/C mode and will force recirculated air. If it's 90 outside and you have it on 66 when you first start it then it should be close to max fan speed and temp within a few seconds. If not then your inside temp sensor may be bad.

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Just another screw-up on Ford's part I guess! Why on earth would they not use cabin temp to control cabin temp? Outside temp can be an input, but ultimately the two are not related. I've never had a car that anoyed me so much on a daily basis.

 

It has already been over 100 degrees here in Phoenix 4 or 5 times now, and my Auto does the exact opposite of yours on those days. It tends to raise the fan speed up to full blast with max a/c for a few minutes. This says to me that it does use both sensors when determining fan speed, as akirby suggested. The only VERY ANNOYING part of the system is that re-circ doesn't stay on when on Auto mode. If I turn on re-circ when on Auto mode it turns itself off every few minutes. Sure wish I could figure out how to keep it from turning off when in Auto. UGH!

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It has already been over 100 degrees here in Phoenix 4 or 5 times now, and my Auto does the exact opposite of yours on those days. It tends to raise the fan speed up to full blast with max a/c for a few minutes. This says to me that it does use both sensors when determining fan speed, as akirby suggested. The only VERY ANNOYING part of the system is that re-circ doesn't stay on when on Auto mode. If I turn on re-circ when on Auto mode it turns itself off every few minutes. Sure wish I could figure out how to keep it from turning off when in Auto. UGH!

 

Seems like a very poor implementation of Auto A/C either way. Goal should be to get cabin temp to set point as fast as possible, then adjust accordingly. At least this is the way any of my other vehicles handle this task. I'll have the dealer check out the interior temp sensor. Maybe it is bad.

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I agree with i20sailor. There is a problem here. Today it was sunny and 75 outside. My Temp was set to 68 (as it was when I shut the car off). When I got in the car, the inside temp was very hot, maybe 100 degrees from the sun. When I started the car, the re-circ never went on and the fan speed was not fast. I left it go and it was maybe 20-30 minutes before it was a reasonable temp inside the car. Apparently since it was 75 outside and My Temp was set to 68, the system didn't compute that it needed to cool the car from 100 inside to 68. My car is going into the dealer on Friday for MFT update and I will discuss this with them. It's gonna be a long hot summer in the MKX.

Edited by carfaninpa
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It has already been over 100 degrees here in Phoenix 4 or 5 times now, and my Auto does the exact opposite of yours on those days. It tends to raise the fan speed up to full blast with max a/c for a few minutes. This says to me that it does use both sensors when determining fan speed, as akirby suggested. The only VERY ANNOYING part of the system is that re-circ doesn't stay on when on Auto mode. If I turn on re-circ when on Auto mode it turns itself off every few minutes. Sure wish I could figure out how to keep it from turning off when in Auto. UGH!

 

Re-circ only runs for a short duration since it will get too dry in the vehicle. Also most climate control systems also have a solar load sensor located in the center of the dash top that is also a input parameter to the climate control.

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