AC Always On When Start Car

[RodHower]

I have the same issue with my 2023 Premium AWD. Luckily it remembers my profile since the wife is 10 inches shorter and likes to sit high and all the way forward. I never run the AC unless it goes over 76 degrees, which doesn't happen that often in NE OH. I park in the shade of a deck at work where it stays pretty cool until summer, and even then it doesn't get very hot. I don't have any departure times set either.

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[MachhE-CT]

I you go into the HVac screen. ( icon lower center right of the HVAC control screen you get a screen with more HVAC options. Hit the Systme off button upper left and it will star off even between starts

 

[Mach-Lee]

I used my AC for the first time since buying my MME and now it’s on every time I start the car even when I turn it off before turning car off.
I’ve dug through settings and cannot find anything to address this.
Any ideas?
Thanks

A/C is automatic whether you like it or not. Shutting it off is only temporary (for the rest of the drive unless conditions change). It will automatically turn on when it decides it's required (mostly for dehumidification), sometimes without illuminating the indicator light on the A/C button. FYI, the A/C usually does not take that much energy unless it's very hot outside, so turning it off isn't usually as much of a savings as you think. Personally I would only turn off A/C if I was running very low on range, I don't care enough otherwise.

It's best if people just adopt a "Set It and Forget It" mentality when it comes to the HVAC on the Mach-E (just adjust the temp setting, that's it). Those who want to try to manage the heater, A/C, and fresh air vent themselves are going to frustrated with the automatic logic. Your inputs are only requests, the HVAC control has the final say over what happens for operational efficiency.

 

[mg_gti]

Not sure how turning on the AC can be considered 'operational efficiency'. If I turn something off, it should stay off. Otherwise why even bother having a switch for it?

 

[Willymy]

I have the issue that when it turns itself on without my input, I get really cold air from the vents. Evenb when the outside temp is in the 60's and all I need is the vent

 

[E90alex]

You have to change your mindset somewhat from ICE cars. The AC is also used to cool the battery and drive unit as needed.

It doesn’t matter if you turn the AC button on or off. The car will still kick on the AC compressor as needed for other functions. And if the AC compressor is running anyways, might as well use excess cooling capacity to cool and/or dehumidify the cabin.

 

[ChrisO]

A/C is automatic whether you like it or not. Shutting it off is only temporary (for the rest of the drive unless conditions change). It will automatically turn on when it decides it's required (mostly for dehumidification), sometimes without illuminating the indicator light on the A/C button. FYI, the A/C usually does not take that much energy unless it's very hot outside, so turning it off isn't usually as much of a savings as you think. Personally I would only turn off A/C if I was running very low on range, I don't care enough otherwise.

It's best if people just adopt a "Set It and Forget It" mentality when it comes to the HVAC on the Mach-E (just adjust the temp setting, that's it). Those who want to try to manage the heater, A/C, and fresh air vent themselves are going to frustrated with the automatic logic. Your inputs are only requests, the HVAC control has the final say over what happens for operational efficiency.

I'm sorry, but in this context this information isn't correct.

One needs to separate what the car needs from the controls for the user.

Yes, it is true that the cooling/heating system will always be on for maintaining the battery, but that isn't what is being referred to in this discussion. Note it would be extremely foolish of the engineers to allow the user to control the colling/heating of the battery system, with the only exception being to let the system know that pre-conditioning should happen at some point in time.

There is zero reason why the cooling/heat/fan has to be routed to the passenger compartment all the time. And that is what this discussion is about.

And I can tell you that my 2004 Mach-E Select with 10.0.2 (and before) software allows us to turn it completely off (in the passenger compartment). We don't have to turn it off every time we get into the car. I have no idea why this isn't working this way for others, but clearly it isn't a "requirement".

This isn't just about energy consumed, even though that can be part of it, it is about having a fan blowing on you when you don't want it to.

 

[mg_gti]

You have to change your mindset somewhat from ICE cars. The AC is also used to cool the battery and drive unit as needed.

It doesn’t matter if you turn the AC button on or off. The car will still kick on the AC compressor as needed for other functions. And if the AC compressor is running anyways, might as well use excess cooling capacity to cool and/or dehumidify the cabin.

If my car has been parked at an ambient temperature of 15C, and I start it, there is zero justification for overriding the previous user setting and starting the AC. Yet this is what happens.

This is clearly a software bug but I don't suspect it is very high on Ford's priority list.

 

[azerik]

Yeah, mine does the AC on and undo cabin re-circ every time I start the car, auto or not. I find it only annoying because I'm in the weather where I can drive home in the evening with the windows down and AC off. But when I start the car in the morning the AC and fan ramp up and I left the windows down. Just that turboprop winding up as I'm backing out lol.

 

[RmP]

I'm sorry, but in this context this information isn't correct.

One needs to separate what the car needs from the controls for the user.

Yes, it is true that the cooling/heating system will always be on for maintaining the battery, but that isn't what is being referred to in this discussion. Note it would be extremely foolish of the engineers to allow the user to control the colling/heating of the battery system, with the only exception being to let the system know that pre-conditioning should happen at some point in time.

There is zero reason why the cooling/heat/fan has to be routed to the passenger compartment all the time. And that is what this discussion is about.

And I can tell you that my 2004 Mach-E Select with 10.0.2 (and before) software allows us to turn it completely off (in the passenger compartment). We don't have to turn it off every time we get into the car. I have no idea why this isn't working this way for others, but clearly it isn't a "requirement".

This isn't just about energy consumed, even though that can be part of it, it is about having a fan blowing on you when you don't want it to.

I think and I could be wrong, most likely am but I read in UM that AC might need to run for at least 2 minutes every so often so the system functions properly.

 

[azerik]

That's what it's doing when I back out of my garage that's 90 degrees. When I park the night before fans. are off etc and windows down because it's low 70's. But 3pm the next day my garage is 90, thus the car is 'warmer' so it kicks on. If i drive a block and a half down the street it's off by then. But the ac in the car will be drooling cold air in the cab.

Like Lee said, the auto-logic is always going to win. I've tried just adjusting the temp, which is better but not great. Whatever they did when they borked the temp unit and started trying to offset by deltas wasn't good, yet they won't fix it.

 

[ChrisO]

I think and I could be wrong, most likely am but I read in UM that AC might need to run for at least 2 minutes every so often so the system functions properly.

"Every so often" is a very loose term, doesn't really capture an "exact requirement". What's more it doesn't say anything about if this is referring to cooling the cabin or not.

I asked CoPilot a few questions (just because it can look up the research better than I can) a few questions on this and I think the answers it found are spot on.

Given an outside temperature of 15C/60F to 25C/77F would it require routing cooling to the cabin to keep the battery cool?

At an outside temperature of **15°C to 25°C**, the Mach-E's battery cooling system generally does not require routing cooling to the cabin to keep the battery cool. Here’s why:

- **Battery Cooling Behavior**: The Mach-E uses a liquid cooling system to regulate battery temperature. At moderate temperatures (15°C to 25°C), the battery is unlikely to generate excessive heat that requires additional cooling.
- **Cabin vs. Battery Cooling**: The cooling system can prioritize battery cooling separately from cabin cooling. However, in extreme conditions (either very hot or very cold), the system may share cooling or heating resources between the battery and cabin.
- **Charging Considerations**: When charging at a DC fast charger, the Mach-E prioritizes either heating or cooling the battery, but not both simultaneously with the cabin.

In your specified temperature range, the battery cooling system should function independently without needing to route cooling to the cabin. Would you like more details on how the cooling system operates in different conditions?

Does the Mach-E require the AC to run from time to time so that the system will function properly?

Yes, the Mach-E's **AC system does need to run periodically** to ensure proper functionality, but not necessarily for cabin cooling. Here’s why:

1. **Battery & Drive Unit Cooling** – The AC compressor is used to cool the battery and drive unit as needed, regardless of whether the cabin AC is turned on or off.
2. **Automatic Climate Control** – Even if the AC is manually turned off, the system may still activate it for dehumidification or cooling purposes.
3. **System Maintenance** – Some users have reported that the AC might need to run for at least **two minutes periodically** to maintain proper system function.
4. **Cooling System Redesign (2023.5+ Models)** – Newer models integrate cooling circuits more efficiently, allowing excess cooling capacity to be used for battery temperature regulation.

While the AC system may activate automatically, it does not always mean cooling is routed to the cabin. Would you like more details on how the Mach-E manages thermal regulation?

Yes, give me the details on how the Mack-E manages thermal regulation.

### **Mach-E Thermal Regulation Overview**
The Ford Mustang Mach-E uses a **complex thermal management system** to regulate battery temperature, cabin climate, and drivetrain cooling. Here’s how it works:

#### **1. Battery Cooling & Heating**
- The Mach-E employs **liquid cooling** to maintain optimal battery temperature.
- A **battery coolant chiller** is used to transfer heat away from the battery.
- The **heat pump (2025 models)** improves efficiency by using refrigerant to transfer heat between components.
- The system can **prioritize battery cooling** over cabin cooling when necessary.

#### **2. AC Compressor & Cabin Climate**
- The **AC compressor runs automatically** when needed, even if the cabin AC is turned off.
- Excess cooling capacity from the battery system can be used to **dehumidify or cool the cabin**.
- The **heat pump system (newer models)** allows for more efficient heating and cooling.

#### **3. Drive Unit & Power Electronics Cooling**
- The **drive unit and power electronics** also require cooling, which is managed by the same liquid cooling system.
- The **coolant pumps and valves** direct cooling where needed.

#### **4. System Complexity & Efficiency**
- The Mach-E’s thermal system is **more complex** than some competitors, with multiple pumps, valves, and heat exchangers.
- **Tesla’s "octo-valve" system** is more integrated, reducing complexity and potential failure points.
- Ford’s approach prioritizes **modular design**, but it has more components that could lead to leaks or inefficiencies.

Would you like more details on how the heat pump improves efficiency in newer models?

Note that my experience is with a 2004 Mach-E so if you don't have a 2023.5+ your experience might be different for that reason.

More than anything else I believe being in control of the fan is the biggest "need" for comfort.

 

[tntschiff]

I am seeing this same issue on my new 2025 Rally. The AC comes on ALL THE TIME even in Acsessory mode. And it is on because I will feel cold air after a minute or two. I took it to the dealer and they gave me the same answer. And note, my 2021 MME I traded in worked JUST FINE.

I left feedback on the Record feedback twice now and will do so once a month. I think this is a SW bug that Ford needs to address, and if this is not normal then I would like the dealership to do something about it (they told me they plugged in the diagnostic system and saw no errors so "nothing is wrong, it is supposed to do this under certain conditions").

 

[Kamuelaflyer]

I am seeing this same issue on my new 2025 Rally. The AC comes on ALL THE TIME even in Acsessory mode. And it is on because I will feel cold air after a minute or two. I took it to the dealer and they gave me the same answer. And note, my 2021 MME I traded in worked JUST FINE.

I left feedback on the Record feedback twice now and will do so once a month. I think this is a SW bug that Ford needs to address, and if this is not normal then I would like the dealership to do something about it (they told me they plugged in the diagnostic system and saw no errors so "nothing is wrong, it is supposed to do this under certain conditions").

It’s not a bug, the system is operating as designed — dealers can’t fix that. Set the temp to something you can live with and turn it off after start if you don’t want any cabin airflow.

Sending feedback is appropriate though.

 

[ChrisO]

It’s not a bug, the system is operating as designed — dealers can’t fix that. Set the temp to something you can live with and turn it off after start if you don’t want any cabin airflow.

Sending feedback is appropriate though.

Well, in my 2024 Select I have no problem with turning it off and it staying off.

I will say one thing about profiles, these settings are certainly not saved in the profiles, they are just remembered from the last time we used the car. I wish they were. My wife and I sometimes switch who is driving and like different settings for the temperature.

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