Another Climate Control Question/Problem - UPDATE RESOLVED!!

[Muscam1]

Saw a good discussion here on a similar HVAC question so I thought it would be good to start a new thread with my particular situation.

2019 Lariat, 96k

Last winter I thought I had a bad driver's side temp actuator. Heat was coming from the upper vents no matter how low I set the temp (passenger side worked fine) ...so I threw some time and money at it - was a fairly inexpensive and simple replacement, but it did not fix my problem.

What appears to be happening is that when the outside temp is around 60 degrees in the morning for example, when I ask for heat, it comes out normally from the driver and passenger sides. As the trip continues and the outside temp reaches around 70 degrees, the driver's side continues to pump out heat from the upper directional vents no matter how low I set the air (both in auto and manual mode as I recall) or if I try to change air flow to the lower vents. The passenger's side works fine - both upper and lower vents and temp when in the single and dual modes.

Never any "clicking" noises and the driver's side temp actuator I replaced looked fine.

I saw some discussions about distribution air temp sensor and temp/humidity sensors that might be my problem.

@airline tech or others - any comments or suggestions?

Thanks--Marc

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[dtech]

Thermistors are generally used to regulate temps and they are cheap (<$20), usually accessible for ease of replacement and occasionally fail. But unfortunately sounds like you may have the blend door issue. Can't recall if ford has a diagnostic mode in the system, some designs do.

 

[Frenchy]

Assuming you are talking about the temperature not changing I would take it to your local dealership. Chances are you may have a problem with the HVAC Distribution box being warped

 

[MarioCart]

the clicking is only one symptom of a blend door issue.

 

[Cmar]

We don't seem to suffer as much from the blend door problems as much as you do over there but when Explorers where imported here in the 1990's and early 2000's it was a common problem.

Over here the main issue has been the actuators, my own car suffers from it, they are a cheap and nasty piece of gear that probably cost $2.00 to make in Thailand (but Ford charges 30 times as much for as a spare part) but regularly fail when the grease on the worm gear runs in the summer heat here, and contaminates the contact track, resulting in the clicking noise as the actuators repeatably try to find the home position but can't make contact. Eventually they wear out, permanently leaving you stuck on cool or hot. You can replace them, but eventually the same thing happens again. If you catch them early, you can remove them and split them apart and clean out the contact paths with contact cleaner, and put them back which also fixes the issue. There was a separate but related issue where the HVAC program was forcing the actuators to move too far resulting in a similar problem as they were forced up against the end of travel of the flap. Ford did release a software update that reduced the number of steps the motors traveled to try and alleviate this.
This is ridiculous, Ford has over 100 years experience in building cars, none of our other Japanese or Korean built vehicles we have now, or have ever previously owned, has ever suffered from this.

 

[airline tech]

Saw a good discussion here on a similar HVAC question so I thought it would be good to start a new thread with my particular situation.

2019 Lariat, 96k

Last winter I thought I had a bad driver's side temp actuator. Heat was coming from the upper vents no matter how low I set the temp (passenger side worked fine) ...so I threw some time and money at it - was a fairly inexpensive and simple replacement, but it did not fix my problem.

What appears to be happening is that when the outside temp is around 60 degrees in the morning for example, when I ask for heat, it comes out normally from the driver and passenger sides. As the trip continues and the outside temp reaches around 70 degrees, the driver's side continues to pump out heat from the upper directional vents no matter how low I set the air (both in auto and manual mode as I recall) or if I try to change air flow to the lower vents. The passenger's side works fine - both upper and lower vents and temp when in the single and dual modes.

Never any "clicking" noises and the driver's side temp actuator I replaced looked fine.

I saw some discussions about distribution air temp sensor and temp/humidity sensors that might be my problem.

@airline tech or others - any comments or suggestions?

Thanks--Marc

So, if I understand correctly, you have zero temp control (other than heat) from the driver's side.
Have you hooked up scanner and found any codes? and what was the initial code that drove you to change the door actuator?

When you replaced the actuator did you calibrate it?
I do not know if it is actually required but the manual calls for the FCIM connector to be disconnected then connect the door actuator and then reconnect the FCIM connector.
But with you stating that is was no-help, then this may not be an issue.
If you have a scanner that will show actuator positions, this can be seen in percent (travel) 0-100

Are you able to get Footwell Air on the Driver's Side?

There are (2) Temp sensors in the air distribution ducts. 1 is Panel (vents) and the other is footwell both on the driver's side.

If I understand you are not getting the air flow to move from the vents on the driver's side, I have a hunch the Driver's Footwell Temp sensor has failed and the system is only using the only good sensor (The Vent)

Hopefully you can pull a code to pinpoint it down to be sure as the Temp Humidity sensor appears to be working since you have normal ops on the passenger side.

 

[dtech]

This is ridiculous, Ford has over 100 years experience in building cars, none of our other Japanese or Korean built vehicles we have now, or have ever previously owned, has ever suffered from this.

agree, very telling regards the approach to quality and also the mind set around customer satisfaction. It's 2nd rate.

 

[Muscam1]

Thanks for the quick response Airline Tech!

To clarify a bit - when I first start the truck when the outside temp is around 70 degrees or higher the driver side air conditioning and vent controls work normally. The problem is when I start the car when outside temp is around 60 degrees or lower with the heater on. When the outside temp moves up to around 70 degrees - the driver side only blows heat through the upper side vents no matter how cold I set the temp. Note - I tried shutting the truck off and restarting when this happened but it still stayed in the heat/side vent condition. Again, the passenger side heat/air conditioning and vent control works normally.

I spend a lot of time on the road where I start in the morning when it's a little cold and still on the road when it gets warmer as the day goes on.

I didn't replace the actuator because it was throwing a code. I replaced it because "I thought" it would fix my problem based on my symptoms and what I had read on various forums. Yes - I was throwing money away but it was a cheap potential fix.

I went to an Autozone and used their scanner. No codes were found. Not sure if I need a deeper level diagnostic tool.

Thanks for the ongoing discussion.

Marc

 

[airline tech]

Either Forscan or a High-End Scanner, capable of reading (B) Body Codes is needed to see the code if one is generated.
Plus, a High-End Scanner or Dealer Level Scanner can view the actual actuator positions and (live) sensor readings.
By your description you appear to have a failed Temp Sensor, the sensor is resistance based.
So, when you have - Heat Blowing = Resistance Falls
AC Blowing = Resistance Rises
The FCIM uses this sensor information to control the desired (selected) cabin air, by either opening or closing the Temp Door actuator.

So, without a code to pinpoint what is failing, I am guessing one of 3 things.
One of the (2) Temp Sensors

Driver's Air Temp Door Actuator, since that was replaced, we can rule out the actuator itself, but the door may be binding and not allowing the actuator to full travel (Open & Closed), this is the issue that requires full HVAC Housing replacement. But this will generally be noted by a loud popping noise as the actuator gears are jumping and binding trying to force the door past the binding force.

Another note: If you have noticed when it Auto and you are using Heat, and let's say OAT = 32 Deg
The FCIM is programmed to move the Air Distribution, to the Floor and Defrost.
When using the AC is when you most note the air coming from the Front Facing Dash Vents.

If it is one of the temp sensors, you will be looking for one of these codes.

B10B5-11 - Left Panel Air Discharge Temp - Short to Grd
B10B5-15 -Left Panel Air Discharge Temp - Short to Battery or Open

B10B6-11 - Left Floor Air Discharge Temp - Short to Grd.
B10B6-15 -Left Floor Air Discharge Temp - Short to Battery or Open

These sensors use a 5-Volt Reference circuit (separate source for each) but they share a signal return circuit (Ground), so my best guess is one of the sensors has failed, thus the FCIM is taking what it is reading from both sensors and combining the readings (an inaccurate reading) and the FCIM is using a calculated average of them, so the Air Temp door does not close, and remains open to allow heat to flow from the Heater Core.

The Air Temp Door & Actuator - Controls the open & close (amount of heated air from the heater core housing) the control of how far to open & close comes from the temp sensors.

Note: The Temp / Humidity Sensor is also on that Signal Return Circuit, but by your issue I am leaning towards a sensor on the driver's side and my first guess would be the Footwell Sensor.

 

[Muscam1]

Thank you for the detailed and informative response! This has helped me and I'm sure others in the future who may have the same issue as me.

Looks like I need to invest in a forscan device.

I'll keep the forum updated as get the device and scan for codes.

Again - really appreciate all the input.

This forum is GREAT!!

Marc

 

[airline tech]

Since I was in the garage, I hook up my Scanner (Autel) and played with it a bit.

Here are the main PID's for the Climate Control that can be viewed. I do not know if Forscan will display these or not.

Notes: For T/Shoot
Mode Door Position: (Normal Readings as Follows)
Defrost = 100%
Panel = 0%
Floor = 50%
Blend - Panel/Floor = 25%

Left / Right Blend Door (This is the Temp Actuator/ Door) Position, this will check max travel open and closed.
Any selected temp in between the (percent) will vary.
Hi (Heat) = 0%
Lo (Cold) = 100%

Left Discharge Panel Temp / Left Discharge Floor Temp
These temps will vary but should be close to each other, if mode is placed in Blend (Panel/Floor) if you wait about 5 minutes or so the temps should be near equal.

External Amb Temp - Should match OAT Temp, using your phone etc.

Internal Amb Temp - This is the Temp/Humidity Sensor, this reading will read high and or low, if just sitting still as the heat/cold air is rising up from the floor vents through the dash.

 

[Muscam1]

Man - wish you were closer to me Thanks for the info.

I've loaded down Forscan and have ordered a OBDLink EX FORScan OBD Adapter that's on its way.

Not too familiar with using diagnostic tools like these but looking forward to learning!

Marc

 

[AKATIREGUY]

There is an SSM for the heater box issue. I just ordered a box for one of mine, after replacing the actuator. FCIM performs a sweep to calibrate when you first start the truck. You can listen close and hear all the actuator motors perform the sweep. If a door is binding, the FCIM will register that as the doors stopping point. So you can not command it past that. It becomes the new full open point. You will want to order a heater box. btw there is a reason the actuators were on back order, everyone was trying the cheap and easy fix.... =(

 

[Frenchy]

There is an SSM for the heater box issue. I just ordered a box for one of mine, after replacing the actuator. FCIM performs a sweep to calibrate when you first start the truck. You can listen close and hear all the actuator motors perform the sweep. If a door is binding, the FCIM will register that as the doors stopping point. So you can not command it past that. It becomes the new full open point. You will want to order a heater box. btw there is a reason the actuators were on back order, everyone was trying the cheap and easy fix.... =(

Everyone thought the cheap fix was the way to go when the HVAC Distribution Box was warping so...... ????

 

[Muscam1]

Ok - did a DTS scan for codes and only got a B11DB:08 (battery monitoring module). No other BdyCM or FCIM codes. What the heck?

In regard to the B11D8 code - I had my battery replaced last month and from that time on I noticed that my Auto Start/Stop had quit working. Just looked under the hood and the BMM cable was not plugged in...so that took care of that problem.

After fixing the BMM plug I ran the self-tests on the BdyCM and FCIM modules and they all completed successfully.

Guess I'll have to keep an eye on my original climate control issue. It's that time of year here when the temp is cold in the morning and considerably warms up in the afternoon, where I'm seeing my problem. Maybe pull codes again right after it happens?

Marc

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