Can someone explain our HVAC system?

[DefNotBuddyLee]

Ford has decided to complicate even the non auto ventilation system. It randomly will allow outside air to refresh the cabin from what I can tell.

Like @Ducati1098 said, due to cabin air purge. I believe this started after all of the issues with PD Explorers that experienced carbon monoxide issues. I know it was a big enough issue in Austin that the local PD pulled the fleet and installed carbon monoxide detectors in the Explorers while they were trying to troubleshoot due to some officers getting carbon monoxide poisoning. I believe the hotfix was to have the recirc occassionally turn off to allow outside air in the cabin.

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[Area51BS]

I have noticed that even fan level 1 is more than sufficient except when max cold or max hot is required. Anything above 1 is overkill at other times

That’s a good thing. The system is plenty adequate. And summers in FL require high speed to get cooled down.

 

[nabronco21]

I like the high pitched whistle when the fan is on the highest setting. Also when the defrost circuit isn't selected it sounds like one of the doors isn't closed the whole way.

 

[Fonz54]

I never use the recirculate mode. I have noticed that at times I will be driving along and the air just stops coming out of either the dash vents or the floor vents. When I press the vent selector it show that neither the dash or the floor vents are selected. If I touch one or the other the air will start to flow again. Another weird observation is that sometimes for no apparent reason the defroster vents for the front door windows begins to blow air but then will stop. Is this part of the air purging mentioned presviously in this thread?

 

[wjtinfwb]

I've now had my OBX for roughly a year and a half and this vehicle has one of the oddest HVAC systems I've ever encountered. I'm very curious if it operates differently based on outside temp.
I keep my temp at about 70F almost year round. During the summer months, 70F blows cold air with A/C turned on. Once the outside temp dips below about 60F, the HVAC blows hot air at 70F internal even with the A/C turned on. During summer, recirculate stays on at all times. During winter, even with A/C turned on, recirculate turns off at about 60 seconds and needs to be turned back on if desired.

I've noticed other quirks as well. What in the world is going on with this crazy HVAC system?

All but base level models have a Automatic Temp Control "feature". If the "AUTO" indicator is lit, the system will adjust temperature, fan speed, recirculation etc. to control the temp to the preset degree, providing heated air if the cabin temp is below the desired set temperature. It also routs air through the defroster vents to avoid windshield fogging and will use the recirculate function in warm weather as cooling 75 degree inside air is much easier than 90 degree outside air. You can override all of this by pushing the Auto switch to turn off the automatic function or by managing the fan speed or routing of air though various vents to pushing the appropriate button.

 

[pdilecce]

I've now had my OBX for roughly a year and a half and this vehicle has one of the oddest HVAC systems I've ever encountered. I'm very curious if it operates differently based on outside temp.
I keep my temp at about 70F almost year round. During the summer months, 70F blows cold air with A/C turned on. Once the outside temp dips below about 60F, the HVAC blows hot air at 70F internal even with the A/C turned on. During summer, recirculate stays on at all times. During winter, even with A/C turned on, recirculate turns off at about 60 seconds and needs to be turned back on if desired.

I've noticed other quirks as well. What in the world is going on with this crazy HVAC system?

I have owned over 15 cars from diverse manufacturers with AC.

In all cases, the AC compressor will come on when in DEF mode. Front windshield defrost. This is done to achieve the quickest defrosting or defogging of the windshield.

So, if you leave the AC in Auto mode... it might be the reason for this sequence of operation.

 

[jzweedyk]

Ford uses the outside temp sensor to regulate the inside air. My problem is that the outside temp sensor does not work at low speed. So I go on a trail in the morning when cold, and then the outside temp heats up, but the Bronco thinks it is still cold outside and so the air conditioning will not cool much. I wish they would only monitor the inside temp and cool or heat to the temp I have selected. My 19 Raptor did this as well.

 

[amazingjason]

I've noticed that when I have a low temp set in warm weather, it blows cold air into the cabin without A/C on. But, its cold, not just ambient temp, and I'd swear it feels like air conditioning. Again, A/C isn't on, and I hate auto HVAC so that's not a factor.

How is the air that cold without the A/C being on? Are we sure there isn't some kind of mild or passive A/C when its fresh air that's on the low 60s or cold setting?

There is also a huge difference in air temp from low to one notch above low with the a/c off.

 

[Scott R Nelson]

All but base level models have a Automatic Temp Control "feature"...

And that's something that I prefer about the Base model. I drove a Wildtrak at the Moab Off-Roadeo and my daughter has a Black Diamond that I've also driven and I find it easier to deal with the HVAC on the Base than on the ones that try to do more for you. It's totally easy to adjust the temperature if I want it to be a little warmer or colder than what it's currently set to. Not all of the "advanced features" are better than the old way of doing things, in my opinion.

 

[Herewegoagain]

I've now had my OBX for roughly a year and a half and this vehicle has one of the oddest HVAC systems I've ever encountered. I'm very curious if it operates differently based on outside temp.
I keep my temp at about 70F almost year round. During the summer months, 70F blows cold air with A/C turned on. Once the outside temp dips below about 60F, the HVAC blows hot air at 70F internal even with the A/C turned on. During summer, recirculate stays on at all times. During winter, even with A/C turned on, recirculate turns off at about 60 seconds and needs to be turned back on if desired.

I've noticed other quirks as well. What in the world is going on with this crazy HVAC system?

I think it's junk! Can't figure out how to completely shut the fan off! I'm older so I'm not as good at all this so called technology as most of the younger crowd!

 

[Ducati1098]

I think it's junk! Can't figure out how to completely shut the fan off! I'm older so I'm not as good at all this so called technology as most of the younger crowd!

You press the power button

 

[mikeeshim]

I especially enjoy it when recirc turns off by itself while on the highway and the air is blasted in, even at the lowest setting... almost like it's being straight piped into the cabin.

 

[Broncotrax]

I will say it works far better that it does in my'69 Bronco. Makes me happy.

 

[j_marinelli]

Thank you for sharing this @Ducati1098 .

What this explains does occur and really isn't too annoying. Its when it does the turn off (light goes off) that it get's annoying. I find it to occur when I have the temp set close to what it says the ambient temperature is. Right now our mornings are cooler so it happens pretty much every morning.

 

[CarGuy]

Use these two buttons for optimal HVAC comfort (the HVAC was not designed or executed well

)

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