I'm new to the diesel having just gotten mine after having an Ecoboost F150.

Question -- once the truck gets up to normal operating temps, should the climate control be capable of removing all the fog from the side windows??

 

For me... yes once it is up to operating temp it does remove MOST of the frost from the side windows (depending on conditions) if it is just me in the truck. Even in the auto mode. From time to time, I have to switch to defrost to clear them then back to auto.

However, if I get my wife and kids in there bantering away (increasing the humidity) sometimes it does not keep them clear in the auto position. Have to switch to defrost. But once they are clear and the family settles down they usually stay partially clear in auto (enough to use the mirrors).

This is all assumint it is very cold outside. Above 0F, no issues for me.

It's really going to depend on temperature and humidity levels in your area, it's pretty dry here.

 

Same here...

 

I agree with Darren and Andre, but I will add that during times where the humidity is high and ambient temperature is at or near the dewpoint, I have needed to direct my side vents at the side windows to keep them clear. Humidity levels are low in the winter so it isn't a problem but in the fall when temps start dropping and the humidity level is still high, it can be a problem that the defroster won't take care of.

 

Good point

Also, when I pick the kids up from sports and they are sweating like pigs, it takes a bit for the windows to clear up. I don't think that is the trucks fault at all...kids are just really hot and steaming/stinking up the truck.

 

I find keeping the air moving helps a lot too. Instead of having the heat on bust with fan speed of one, I'm comfortable with a temp of 23-26* and fan speed 3-4 for highway driving. And its usually on defrost/floor.

 

Thanks all -- I'm finding that the past couple of days it's "better", but not what I would expect. I'm keeping the front windshield clear now...the front side windows take forever to clear, and are easily re-fogged...

The back seat side windows?? Never clear on their own....even once the truck is up to temp...and even if I put them down and back up to clear them and introduce some cool, dry air into the cab, they re-fog.

For comparison, I've noticed that I don't see other vehicles on the road with fogged windows, so I still think the AC isn't doing an adequate job dehumidifying the air.

I NEVER had this issue at all in my F150 Ecoboost...

I'm still working with the dealer on the issue so will keep you posted. I do appreciate the feedback...sounds like I may still have some residual fog, but considering I drive alone in the truck the majority of the time, I'm expecting nearly-clear windows....

 

I always keep it on defrost/floor as well once warmed up, start with just defrost though.

 

Just to throw it out there, you sure you aren't on recirculation mode?

 

No...definitely not. Although -- when I called the dealer on Monday this week to explain the problem, the guy I talked to suggested that I do that...he is clearly a technical wizard.

 

Would putting the AC on and setting the temp up high help ?

The few times that's happened to me,
that's what I did and the windows cleared almost instantly...

or maybe it's this 'smart' truck automatically turning on defrost even though I turn on ac to pull the humidity out ???? dunno, but it works for me !

 

I've tried the AC button -- I can't tell that it's making a difference...of course, by that time, the windows are so fogged up I need a lighthouse to guide me down the road...

I may try the AC button when I first start up to see if that helps prevent the fog.

Supposedly, when you engage the defroster or the floor/defroster modes, it uses the AC as needed to dehumidify the air... so far, I'm not seeing it...

 

For a 2011 at least (that is the manual I have) the A/C is not going to do any dehumidifying below 32F. I copied the whole section but see the red below.

Dual Automatic Temperature Control (DATC) System

System Operation
The Dual Automatic Temperature Control (DATC) system maintains the selected vehicle interior temperature by heating and/or cooling the air.

• During A/C operation, the system reduces the relative humidity of the air.
• The driver may override the automatic mode of operation.
• The temperature control setting determines the desired air temperature.
• The blower motor control override button varies the blower motor speed.
• The driver side and passenger side temperature settings can be individually controlled.

When the DATC system is set to AUTO the air distribution direction, blower motor speed and A/C compressor operation are automatically controlled based on the temperature(s) selected.
The DATC system manual override settings:

• allow the air distribution direction to be manually selected.
• allow the blower motor speed to be manually selected.
• allow recirculation mode to be manually selected in all modes except DEFROST. The A/C request can be cancelled by pressing the A/C request switch, turning the indicator OFF.
• allow A/C compressor operation to be manually selected except in DEFROST.

Remote Start System Behavior
When the remote start feature is used, the climate control system automatically sets certain parameters in an attempt to achieve a comfortable cabin temperature. These parameters are set based on outside air temperature. During remote start, the outside air temperature is continually evaluated and HVAC system behavior can change if the outside air changes between cold, moderate and warm temperatures.
For cold ambient air temperatures as determined by the HVAC module AUTO mode to request heat:

• the airflow mode is set to FLOOR/DEFROST.
• the temperature is set to 22°C (72°F).
• the blower speed is set to AUTO.
• the air inlet mode is set to AUTO.
• the auxiliary electric heater is enabled if needed (diesel engines only).

For moderate ambient air temperatures as determined by the HVAC module AUTO mode to request heat or cooling:

• the airflow mode is set to the AUTO.
• the temperature is set to the last user setting (Temperature setting is limited to 18°C (65°F) minimum and 29°C (85°F) maximum. If the temperature is set above or below that range, it will use the minimum or maximum value.).
• the blower speed is set to the AUTO.
• the air inlet mode is set to AUTO.
• the auxiliary electric heater is enabled if needed (diesel engines only).

For warm ambient air temperatures as determined by the HVAC module AUTO mode to request cooling:

• the airflow mode is set to AUTO.
• the temperature is set to 22°C (72°F).
• the blower speed is set to AUTO.
• the air inlet mode is set to AUTO.
• the auxiliary electric heater is not enabled (diesel engines only).

System Airflow and Mode Description
AUTO

When AUTO is selected:

• the temperature control setting is manually set to the desired setting.
• the air inlet door is automatically controlled by the HVAC module, based on the temperature setting.
• the mode door is automatically controlled by the HVAC module, based on the temperature setting.
• the temperature blend doors are automatically controlled by the HVAC module, based on the temperature setting.
• the A/C compressor is automatically controlled by the HVAC module, based on the temperature setting. The A/C compressor will not operate if the outside temperature is below approximately 0°C (32°F).
• the A/C request button or the RECIRC request button, if pressed, transfers the system to semi-auto operation.
• the blower motor is ON. The blower motor speed is automatically controlled by the HVAC module, based on the temperature setting, but can be manually overridden.

OFF

When OFF is selected:

• the RECIRC request button is disabled.
• the air inlet door closes off outside air and admits only recirculated air.
• the defrost/panel/floor door actuator is in the DEFROST position.
• the A/C request button is disabled.
• the blower motor is OFF.

Max A/C

When MAX A/C is selected:

• the air inlet door closes off outside air and admits only recirculated air.
• the RECIRC button is disabled and the indicator is illuminated. (RECIRC forced ON).
• the defrost/panel/floor door directs airflow to the instrument panel A/C registers.
• blended air temperature is available.
• the A/C request button is illuminated and disabled.
• the A/C compressor operates if the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

PANEL

When PANEL is selected:

• the RECIRC request button is enabled. If the RECIRC request button is selected (indicator ON), the air inlet door actuator closes off outside air from entering the passenger compartment. If the RECIRC request button is not selected (indicator OFF), the air inlet door admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the instrument panel A/C registers.
• blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator ON), can the airflow temperature be cooled below the outside air temperature.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

PANEL/FLOOR

When PANEL/FLOOR is selected:

• the RECIRC request button is enabled. If the RECIRC request button is selected (indicator ON), the air inlet door closes off outside air from entering the passenger compartment. If the RECIRC request button is not selected (indicator OFF), the air inlet door admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct and the instrument panel A/C registers. A small amount of airflow from the side window demisters and defrost duct is present.
• blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator ON), can the airflow temperature be cooled below the outside air temperature.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

FLOOR

When FLOOR is selected:

• the RECIRC request button is enabled. If the RECIRC request button is selected (indicator ON), the air inlet door closes off outside air from entering the passenger compartment. If the RECIRC request button is not selected (indicator OFF), the air inlet door admits only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct. A small amount of airflow from the defroster duct and side window demisters is present.
• blended air temperature is available. Only when A/C compressor operation has been selected by pressing the A/C request button (indicator ON), can the airflow temperature be cooled below the outside air temperature.
• the A/C request button is enabled. The A/C compressor operates and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

FLOOR/DEFROST

When the FLOOR/DEFROST is selected:

• the RECIRC request button is disabled. The air inlet door opens, admitting only outside air into the passenger compartment.
• the defrost/panel/floor door directs airflow to the floor duct, the defroster duct and the side window demisters.
• blended air temperature is available.
• the A/C request button is enabled. The A/C compressor operates automatically and the indicator illuminates if the A/C request button is selected and the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

DEFROST

When DEFROST is selected:

• the RECIRC request button and indicator is disabled. Regardless of button and indicator status, the air inlet door admits only outside air into the passenger compartment.
• the defrost/panel/floor door actuator directs airflow to the defroster duct and side window demisters. A small amount of airflow from the floor duct will be present.
• blended air temperature is available.
• the A/C request button indicates the last status and the indicator can be toggled. To reduce fogging, the A/C compressor operates automatically, regardless of indicator status, if the outside temperature is above approximately 0°C (32°F).
• the blower motor is ON.

 

There is nothing in the symptom chard for "does not defrost properly" but maybe you can have them do the second one (pinpoint H) which is basically CHECK EVERYTHING

<TABLE border=1 rules=groups cellSpacing=0 cellPadding=3 width="90%"><CAPTION>Symptom Chart — Climate Control Systems NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart.
</CAPTION><COLGROUP><COLGROUP><COLGROUP><TBODY><TR>< TH>Condition </TH><TH>Possible Sources </TH><TH>Action </TH></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• No communication with the HVAC module

</TD><TD>

• Fuse(s)
• Wiring, terminals or connectors
• HVAC module communication network

</TD><TD>

• REFER to Section 418-00 .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• Unable to duplicate the customer concern and no DTCs present

</TD><TD>

• HVAC system and/or related components

</TD><TD>

• GO to Pinpoint Test H .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• Reduced outlet airflow

</TD><TD>

• Wiring, terminals or connectors
• A/C compressor clutch air gap
• A/C pressure transducer
• Evaporator temperature sensor
• A/C clutch relay
• Blower motor
• Blower motor control
• PCM

</TD><TD>

• If the A/C compressor does not cycle, GO to Pinpoint Test M .
• If the A/C compressor cycles normally, GO to Pinpoint Test Q .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The air inlet door is inoperative

</TD><TD>

• Wiring, terminals or connectors
• Air inlet mode door actuator
• Air inlet mode door binding or stuck
• HVAC module

</TD><TD>

• GO to Pinpoint Test I .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• Incorrect/erratic direction of airflow from outlets

</TD><TD>

• Wiring, terminals or connectors
• Defrost/panel/floor mode door actuator
• Mode door(s) binding or stuck
• HVAC module

</TD><TD>

• GO to Pinpoint Test J .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• Insufficient, erratic or no heat

</TD><TD>

• Low engine coolant level
• Plugged or partially plugged heater core
• Temperature blend door(s) binding or stuck
• Temperature blend door actuator(s)
• Auxiliary Heater Control Module (AHCM)

</TD><TD>

• GO to Pinpoint Test K .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The air conditioning (A/C) is inoperative

</TD><TD>

• Fuse(s)
• Wiring, terminals or connectors
• A/C system discharged/low charge
• PCM
• HVAC module
• A/C clutch relay
• A/C compressor clutch air gap
• A/C pressure transducer
• Evaporator temperature sensor
• A/C compressor clutch field coil

</TD><TD>

• GO to Pinpoint Test L .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The air conditioning (A/C) is always on — A/C compressor does not cycle

</TD><TD>

• Wiring, terminals or connectors
• PCM
• A/C clutch relay
• A/C compressor clutch air gap
• Evaporator temperature sensor

</TD><TD>

• GO to Pinpoint Test M .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The air conditioning (A/C) is always on — A/C mode always commanded on

</TD><TD>

• Wiring, terminals or connectors
• PCM
• HVAC module

</TD><TD>

• GO to Pinpoint Test N .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• Temperature control is inoperative/does not operate correctly

</TD><TD>

• Wiring, terminals or connectors
• HVAC module
• Temperature blend door is binding or stuck
• Temperature blend door actuator(s)

</TD><TD>

• GO to Pinpoint Test O .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The blower motor is inoperative

</TD><TD>

• Fuse(s)
• Wiring, terminals or connectors
• Blower motor relay
• Blower motor
• HVAC module
• Blower motor speed control

</TD><TD>

• GO to Pinpoint Test P .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The blower motor does not operate correctly

</TD><TD>

• Wiring, terminals or connectors
• Blower motor speed control
• HVAC module

</TD><TD>

• GO to Pinpoint Test Q .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The electric heater is inoperative/does not operate correctly

</TD><TD>

• Fuse(s)
• Wiring, terminals or connectors
• Auxiliary Heater Control Module (AHCM)

</TD><TD>

• GO to Pinpoint Test S .

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The temperature set point does not repeat after turning the ignition switch OFF

</TD><TD>

• HVAC module

</TD><TD>

• INSTALL a new HVAC module. REFER to Section 412-01 . TEST the system for normal operation.

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• The temperature display will not switch between Celsius and Fahrenheit

</TD><TD>

• HVAC module
• Instrument Panel Cluster (IPC)

</TD><TD>

• If the IPC does not switch between English and Metric, REFER to Section 413-01 and diagnose.
• If only the HVAC module does not switch between English and Metric, INSTALL a new HVAC module. REFER to Section 412-01 . TEST the system for normal operation.

</TD></TR><TBODY></TBODY><TBODY><TR vAlign=top><TD>

• A/C pressure relief valve discharging

</TD><TD>

• High system pressure
• A/C pressure relief valve

</TD><TD>

• CHECK the high side system pressure. If the pressure is below the A/C pressure relief valve open pressure, REPLACE the A/C pressure relief valve. If the system pressure is above the A/C pressure relief valve open pressure, REPAIR the system for a restriction.

</TD></TR></TBODY></TABLE>

 

Full fan speed and a "reasonable temperature" (I don't have the fancy digital HVAC panel display) in windshield/floor venting keeps the windows clear even with 5 best friends riding with me haha. I have the electric cab heater option if that makes any difference. Maybe try to cycle through all the vent options and the recirc door just to make sure nothing is mechanically jammed up?