What does climate control AUTO 1-2-3 actually do?

[dbsb3233]

Has anyone fully figured out what the AUTO 1-2-3 settings do for fan speed? I know the fan speed goes up and down when you rotate between those. But does it still automatically change the fan speed for you? If so, how much? Does 1 actually mean Low-ish (like 1-3 fan speeds), 2 Medium-ish (like 3-5), and 3 High-ish (like 5-7)?

And is there a way to make it fully automatic (i.e. automatically change between 1-7 base on the temp and what's needed)?

It's just very unclear what AUTO 1-2-3 actually do.

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[generaltso]

In my testing, it appears that the different levels of Auto just limit the fan speed. So if you have it in Auto 3, it will be fully automatic and can use any fan speed as needed. Auto 2 does the same, but limits the fan speed to about half. Same for Auto 1, but the fan speed is limited to around 25% or less.

 

[dbsb3233]

In my testing, it appears that the different levels of Auto just limit the fan speed. So if you have it in Auto 3, it will be fully automatic and can use any fan speed as needed. Auto 2 does the same, but limits the fan speed to about half. Same for Auto 1, but the fan speed is limited to around 25% or less.

That's what I had been thinking maybe too, so I tried leaving it on 3 (wanting it to go max if it needed). But then it would never automatically drop to the lowest fan speed even after getting to the perfect temp. It never seems to drop below a medium speed.

 

[generaltso]

That's what I had been thinking maybe too, so I tried leaving it on 3 (wanting it to go max if it needed). But then it would never automatically drop to the lowest fan speed even after getting to the perfect temp. It never seems to drop below a medium speed.

Interesting. Was this with heat or A/C? It seems to work as expected for me, but I've only tried it with heat. Not warm enough yet for A/C.

 

[db4z]

This setting has been on Lincoln's for years and it is to reduce how aggressive the fan curve is to reduce noise in really quiet vehicles.

 

[macchiaz-o]

Besides what @generaltso and @db4z stated, tapping Auto also turns off recirculation and sometimes turns on e-heat, even when cycling from one Auto level to the next.

I think this is wrong and hope it is changed, but I suspect it won't be.

It'd be great if Auto also controlled recirc intelligently. If it's very hot in the cabin relative to outside air temp, then maybe turn off recirc to cool the cabin faster. Then when the temps equalize, turn recirc back on and leave it on.

 

[generaltso]

Besides what @generaltso and @db4z stated, tapping Auto also turns off recirculation and sometimes turns on e-heat, even when cycling from one Auto level to the next.

I think this is wrong and hope it is changed, but I suspect it won't be.

Agreed. I don't mind if it changes e-heat or recirc settings when first enabling Auto, but I don't want it changing those things when I just change the level of Auto.

 

[db4z]

Agreed. I don't mind if it changes e-heat or recirc settings when first enabling Auto, but I don't want it changing those things when I just change the level of Auto.

Recirculation is often turned off by default in auto modes to reduce humidity, which can lead to condensation/window fog, but I agree it would be nice sometimes if it didn't.

 

[dbsb3233]

Interesting. Was this with heat or A/C? It seems to work as expected for me, but I've only tried it with heat. Not warm enough yet for A/C.

Both, I think. On my recent trip, the temps ranged through heat and A/C ranges. It was usually when it was like a perfect 70F outside, well into the drive, when I noticed AUTO3 was still blowing faster than the lowest fan speed. I'd click it down to AUTO2 and AUTO1 and they definitely lowered the fan speed.

What I'm really trying to find out is what exactly is "as expected" on the AUTO1-2-3 settings?

 

[smp]

Page 122 in the Owners Manual has a table indicating the three fan speeds that correspond with the three indicators:

1 - The blower motor speed is reduced. Use this setting to minimize the amount of noise from the blower motor. This setting increases the time taken to cool the interior.

2 - The blower motor speed is moderate.

3 - The blower motor speed is increased. Use this setting to reduce the time taken to cool the interior. This setting increases the amount of noise from the blower motor.

smp

 

[dbsb3233]

Page 122 in the Owners Manual has a table indicating the three fan speeds that correspond with the three indicators:

1 - The blower motor speed is reduced. Use this setting to minimize the amount of noise from the blower motor. This setting increases the time taken to cool the interior.

2 - The blower motor speed is moderate.

3 - The blower motor speed is increased. Use this setting to reduce the time taken to cool the interior. This setting increases the amount of noise from the blower motor.

smp

Thanks. Helps confirm the general intent, but as is common with the owners manual, it's vague on specifics.

It's seeming like there may not be a fully automatic mode?

 

[smp]

Thanks. Helps confirm the general intent, but as is common with the owners manual, it's vague on specifics.

It's seeming like there may not be a fully automatic mode?

I agree. I've found no other explanation / description / table for AUTO. There are tidbits sprinkled around, but they've been confusing me, also.

smp

 

[Deleted member 3663]

I was taught when it is very hot outside, always start the A/C with re-circulation on, and after going for a bit (3-5 mins), turn re-circulation off.

 

[SnBGC]

From the Work Shop Manual.....
Looks like an interesting read.


Control System Logic

When the customer inputs an A/C request into the information and entertainment display unit or by voice command, the APIM sends the request to the GWM over the HS-CAN3. The GWM relays the request to the SOBDMC over the FD-CAN, and the request message is sent to the ACCM over the HS-CAN1. For a list of all the network messages,
Refer to: Controller Area Network (CAN) Module Communications Network - System Operation and Component Description (418-00A Controller Area Network (CAN) Module Communications Network, Description and Operation).


A/C Request

When the ACCM request for cooling, the electric A/C compressor is commanded on when all of the following conditions are met:

• Excessively high or low refrigerant pressure from the A/C pressure transducer is not detected.
• Ambient air temperature is above approximately 0°C (32°F).
• Electric motor coolant temperature conditions are within normal parameters.
• Evaporator temperature is above approximately 2°C (35.6°F).
• Battery state of charge conditions are within normal parameters.

Compressor control and the evaporator temperature are a function of many parameters, not just a straight on/off, to avoid freezing the evaporator. The PCM monitors multiple temperature sensors for correlation including, but not limited to, AAT, ECT Parameter Identifications (PIDs) (as applicable). The PCM runs this logic after an engine off and a calibrated soak period of 6 to 8 hours. This soak period allows the Ambient Air Temperature (AAT) sensor and the other temperature sensors to stabilize and not differ by greater than a calibrated value, typically 16.7ºC (30ºF). If a temperature sensor input is found to be reporting a temperature imbalance the PCM does not allow the A/C compressor operation. When the ACCM receives the A/C request message, it engages the A/C electric compressor. Instead of cycling ON and OFF like a traditional A/C compressor, the A/C electric compressor speeds up or slows down as required. For more information on PCM sensors, refer to the appropriate workshop manual section.

The PCM monitors the discharge pressure measured by the A/C pressure transducer. The PCM interrupts A/C compressor operation in the event the A/C pressure transducer indicates high system discharge pressures. It is also used to sense low charge conditions. If the pressure is below a predetermined value for a given ambient temperature, the ACCM does not allow the electric A/C compressor to engage.

The HVAC control module adjusts the system based on cabin temperature. The HVAC control module also adjusts the air inlet door depending on the humidity measured by the in-vehicle temperature and humidity sensor. If the vehicle cabin becomes too humid and recirculated air is selected, the HVAC control module adjusts the air inlet door to allow more fresh air. When the humidity level drops, it adjusts back to partial recirculated air.


Heating and Ventilation

The heating and ventilation system:

• controls the temperature of the air inside the vehicle.
• reduces the relative humidity of the air inside the vehicle (during A/C compressor operation).
• delivers heated or cooled air to maintain the vehicle interior temperature and comfort level.

The heating and ventilation system uses a reheat method to provide conditioned air to the passenger compartment. Temperature blending is controlled by the temperature doors, which regulate the amount of air that flows through and around the heater core, where it is then mixed and distributed. All airflow from the blower motor passes through the A/C evaporator core.

Vehicles have a cabin heater coolant pump and a cabin coolant heater with coolant circuits to the heater core.


Air Handling

There are 4 door actuators that control the air flow into the passenger compartment:

• Air distribution
• Air inlet
• Driver temperature
• Passenger temperature

All of the door actuators contain a reversible electric motor and a potentiometer. The potentiometer circuit consists of a 5-volt reference signal connected to one end of a variable resistor, and a signal ground connected to the other. A signal circuit is connected to a contact wiper, which is driven along the variable resistor by the actuator shaft. The signal to the HVAC control module from the contact wiper indicates the actuator door position. The HVAC control module powers the actuator motors to move the doors to the desired positions. The desired door positions are calculated by the HVAC control module based on the set temperature, in-vehicle temperature, ambient air temperature and sunload.

When an airflow mode, desired temperature, fresh air, or recirculation mode is selected, the HVAC control module moves the actuator motor in the desired direction.

The HVAC control module may adjust the air inlet door based on the in-vehicle temperature and humidity sensor information to maintain the desired humidity of the passenger cabin air.

The HVAC control module sends a PWM signal to the blower motor control module to regulate the blower speed as necessary. The blower motor control module provides variable ground feed for the blower motor based on the input from the HVAC control module. A delay function provides a gradual increase or decrease in blower motor speed under all conditions.


AUTO

NOTE: For additional information on the climate control features found on the Information and Entertainment Display Unit, Refer to the Owner's Literature.

When AUTO is selected:

• the HVAC system operates in a manner to achieve and maintain the temperature set by the operator.
• the HVAC control module controls the air inlet door to recirculate, partially recirculate or open to the fresh air position depending on the in-car temperature and humidity sensor inputs.
• the airflow mode is automatically controlled by the HVAC module based on the temperature setting.
• the temperature doors are automatically controlled by the HVAC module based on the temperature setting.
• the A/C compressor is automatically controlled by the HVAC control module based on the temperature setting. The A/C compressor does not operate if the outside temperature is below approximately 0°C (32°F).
• the blower motor speed is automatically controlled through the blower motor control module when it receives a PWM signal from the HVAC control module based on the temperature setting, but can be manually adjusted if desired.

OFF

When the system is OFF:

• the air inlet door closes, preventing outside air and allowing only recirculated air.
• the blower motor is off.

MAX A/C

When MAX A/C is selected:

• the air inlet door closes, preventing outside air and admits only recirculated air.
• the recirculated air indicator is illuminated (recirculated air forced on).
• the A/C button is illuminated.
• the A/C compressor operates as long as the outside temperature is above approximately 0°C (32°F).
• the blower motor is commanded to the highest speed. The blower motor speed is adjustable.

PANEL

When PANEL is selected:

• the mode doors direct airflow to the instrument panel registers.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

PANEL-FLOOR

When PANEL-FLOOR is selected:

• the mode doors direct airflow to the floor duct and the instrument panel registers. A small amount of airflow from the side window demisters and defrost duct is present.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR

When FLOOR is selected:

• the mode doors direct airflow to the floor duct. A small amount of airflow from the defroster duct and side window demisters is present.
• the recirculated air request button can be enabled.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

FLOOR-DEFROST

When FLOOR-DEFROST is selected:

• the mode doors direct airflow to the floor duct, the defroster duct and the side window demisters.
• the recirculated air request button can be enabled, but can automatically turn off.
• blended air temperature is available. The airflow temperature can only be cooled below the outside air temperature when the A/C is commanded on.
• the blower motor is on and the speed is adjustable.

DEFROST

When DEFROST is selected:

• the mode doors direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
• the recirculated air request button can be enabled, but can automatically turn off.
• the A/C is automatically commanded on and remains on until the system is either turned off or the airflow mode has changed and the A/C button is pressed.
• the A/C compressor operates as long as the outside temperature is above approximately 0°C (32°F).
• the blower motor is on and the speed is adjustable.

MAX DEFROST

When MAX DEFROST is selected:

• the recirculated air request button is disabled. The air inlet door opens, allowing only outside air into the passenger compartment.
• the air distribution doors operate in combination to direct airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct is present.
• the A/C is automatically commanded on and remains on until the system is either turned off or the airflow mode has changed and the A/C button is pressed.
• the A/C compressor operates as long as the outside temperature is above approximately 0°C (32°F).
• the temperature is set to the highest setting and is not adjustable.
• the fan is set to the highest speed and is not adjustable.
• MAX DEFROST can be exited by pressing the AUTO button.

Remote Start-Pre Conditioning

The system allows you to remotely start your vehicle and to adjust the interior temperature according to the settings that you chose.

When the factory remote start feature is used, the climate control system can be set to run in Auto mode, or can be set to run at the last setting it was set to when the vehicle was last turned off. Refer to the Owner's Literature for information to set up the remote start features.

 

[dbsb3233]

When AUTO is selected:

• the HVAC system operates in a manner to achieve and maintain the temperature set by the operator.
• the HVAC control module controls the air inlet door to recirculate, partially recirculate or open to the fresh air position depending on the in-car temperature and humidity sensor inputs.
• the airflow mode is automatically controlled by the HVAC module based on the temperature setting.
• the temperature doors are automatically controlled by the HVAC module based on the temperature setting.
• the A/C compressor is automatically controlled by the HVAC control module based on the temperature setting. The A/C compressor does not operate if the outside temperature is below approximately 0°C (32°F).
• the blower motor speed is automatically controlled through the blower motor control module when it receives a PWM signal from the HVAC control module based on the temperature setting, but can be manually adjusted if desired.

Thanks. Although for the question of what AUTO 1-2-3 actually does to fan speed, it still tells us nothing other than "it controls it".

Might help the recirc questions a little though.

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