AC still not blending correctly

[RoushTang11]

I swapped out two actuators, the dash/defroster and the driver side blend door (dual zone system). I saw that there is a way to re-calibrate the system by removing the fuse, starting the car and running the AC to allow the System to try to re-calibrate - problem is that without the Fuse (#15 in my 2011 Mustang GT) - the AC will NOT work. So how do you re-calibrate the system? Do I need a special tool/device/reader? Do I have to go to a shop?

 

[Dino Dino Bambino]

No, just remove the fuse for at least one full minute and then reinstall WITH THE ENGINE OFF. That'll reset the SJB and recalibrate the AC system.

Edit:

Pull fuse..with eng running on idle.... or off ?

Engine off.

 

[Pentalab]

No, just remove the fuse for at least one full minute and then reinstall. That'll reset the SJB and recalibrate the AC system.

Pull fuse..with eng running on idle.... or off ?

 

[RoushTang11]

I pulled the fuse with the engine off. Let it sit out for a minute plus. Started the car with the fuse out. Turned the car off and reinstalled the fuse, and then started the engine again, no noticeable change.

 

[JEWC_Motorsports]

A/C Blend door motor | SVTPerformance.com found this for you

 

[RoushTang11]

Thanks @jewc75 - I tried that. I pulled that fuse out with the engine off- but wasn't sure if the engine needed to be running when the fuse was pulled?

 

[redfirepearlgt]

If the recal does not work it may be time to start looking at this from an electrical point of view. Here are the 2011 dual auto climate control prints link.

Willing to help if you are not good with prints.

https://iihs.net/fsm/?d=711&f=055 - Automatic Climate Control System.pdf

If I understand and you have been able to swap the connectors between the defrost and driver side blend units (see prints) C2091 and C232 connectors and you have the same problem at the drivers side blend door then it has to be the blend door assembly...assuming the recal was done right and changed nothing. However if you swapped the connectors and the drivers side now works (when running in defrost mode) and the defrost displays the same symptoms the drivers side box did when correctly hooked up you have either a harness issue or a bad HVAC controller unit. Again this is if I understood correctly what you did when you said you swapped them.

 

[RoushTang11]

@redfirepearlgt - My '11 GT has dual side controls. I removed the driver's side actuator, as well as the defrost/floor actuator (this is the one that was clicking). The clicking has stopped.
I had replaced the driver's side believing that the actuator was faulty because it would sometimes blow cold - and sometimes it would be tepid. Almost like it's taking in ambient air. I would shut the AC off and after about 20/30 minutes I could sometimes turn it back on and it would be running perfectly cold. Or I would need to shut the car off and it would "reset" and start to blow cold again. This tended to happen on long trips, 2-3 hr drives. Lately, which prompted me to change out the actuator was the driver's side was no longer "resetting". If it's cool out side - I can get it to blow cold - but once it gets hot out (77-85F) the car never cools off as only one side is blowing cold. It seems like it would be the recirculate door for only the driver side is open. I hope this makes sense? I live in SoFlo - so being without AC is not really a viable option!

 

[redfirepearlgt]

does the unit generate hot (not just warm air) when you turn it all the way to HI? does it produce cold when you turn it all the way to LO? This is important to know because the cabin temp sensor is not in play in these over ride modes.

We need to start eliminating probable faults and stop just throwing parts at it. so that is the next step from where i sit. do some testing running in lo and then do some in hi. it can sit for both. start it put it ina mode, walk away for 10 minutes after you feel full hot or cold and then return. put a thermometer on the console and observe. would be best to do HI first, then LO. record hi temp read then record lo temp after same amount of time.

 

[RoushTang11]

I am done with parts at the moment. I only changed the DS actuator because I was already changing the defrost/floor motor and thought that might help.

So I ran the car, put it on full hot (90F) - both sides were equally hot.
When I put it on full cold (60F) - the driver's side was about 10-12 degrees warmer than the passenger's. The air was cool - but it is also 73F outside where I am right now.

 

[RoushTang11]

@redfirepearlgt - any suggestions from here?

 

[redfirepearlgt]

it may be that you refrigerant charge is low. i had the same issue with a dual climate control on a buick years ago.that would be the next step. i read up on diagnostics and it appears that the dual climate can generate failure codes within the hvac unit that can only be accessed by the diagnostic snap on unit or possibly a forscan device or app of some type. they cannot be seen as i understand by a common code tool on a tune device or one bought at a parts store for 20 bucks.

we can do some resistance checks and compare between driver and passengerside units next if you want after you double check the refrigerant charge.

 

[redfirepearlgt]

Being that Ford has made it easy for them but difficult for the average person who does not own the 2 million dollar SNAP-ON diagnostics interface we can only do some comparison resistance checks between the drivers side and passenger side blend units to see if there is something odd on the driver side compared to the passenger which is working as I understand.

Prior to beginning this set the control units at the same level of 60 (LO) degrees and allow it to run for a few minutes. Then simply shut the car off without turning off the climate control. I am hoping that the bend doors will stay where last commanded at if you do this so that when you take resistance readings the positions will be the same.

The blend doors receive a position signal to drive the door motor from the HVAC control unit. There is a resistance bridge that provides positioning feedback to the HVAC unit so it knows when to stop driving the motor and hold position when the HVAC position setpoint for that blend door has been achieved. This goes on throughout the controlled process. This is how I understand the blend door to operate. It appears to be a standard closed loop control process:
CMD-SIG START>DRIVE>FEEDBACK SIG>SATISFY>CMD-SIG STOP.

Make sure car is shut off. You may even wish to disconnect the negative and positive battery connections being we are going to perform resistance checks.

First pull C2091 connector on the drivers side blend door unit. Then ON THE UNIT, not on the connector take resistance readings and record across the following pins.

For reference to pin 1 it will be the pin fed by the Blue/White wire in the connector you pulled off.

Measure resistance across the following and record:

pin1 - pin6 (motor winding)
pin3 - pin4 (resistance feedback circuit)
pin3 - pin 2(resistance feedback circuit)

Next pull C2092 connector on the passenger side blend door unit. Again on the unit, not on the connector take resistance readings and record same.

For reference to pin 1 it will be the pin fed by the Brown/Green wire in the connector you pulled off.

pin1 - pin 6
pin 3 - pin 4
pin 3 - pin 2

Put back together and perform the same checks again after starting the car and placing the unit in FULL HEAT.

THis will allow us to see if the doors are both moving the same amount or or there is an issue with the driver side unit. Again assuming that they will stay where last commanded after shutting the car off without turning off the climate control system.

If everything here looks the same then you may wish to take the car to a Ford place and have them run the diagnostic on the climate control because I would not dare assume that the HVAC controller is bad though it would IMHO be pointing to this. I have no idea what one would cost. But certainly way more than a blend door I am assuming.

Hope this helps.

 

[RoushTang11]

Thanks! I'll try this during the week and report back!

 

[redfirepearlgt]

NP

Here is the link to the wiring schematics for the 2011 and the page showing the blend door wiring in case you need to see it. What we will be checking is the resistance of the motor and the resistance of the variable resistor feedback circuit. The link below takes to that page.

https://iihs.net/fsm/?d=711&f=055 - Automatic Climate Control System.pdf&p=2

 

[RoushTang11]

@redfirepearlgt
Just out of curiosity - the wires in which pattern?
1 - 2
3 - 4
5 - 6

or

1 - 4
2 - 5
3 - 6

The passenger side blend door will be a bugger to get a reading on while in the car. Do you recommend removing? or will that alter the reading?

 

[redfirepearlgt]

I explained the pin to pin checks in reply #13. I also provided the schematics.

Red probe C2091 pin1 - black probe C2091 pin6...and so on. I provided you the wire color code so you would know what pin is pin #1.

Make sure you have read my statements closely. Then read them again. I am not an auto technician. I troubleshoot electronic/electromechanical/electrical complex equipment for a living. I am applying that here as I have when I have helped other people out. Sometimes we have resolved the problem other times we were unable to isolate an electrical fault. I do this for the fun of it and to learn myself as well. My grandfather said that if you learn one thing new every day you will always stay young mentally. I do this to help myself and hopefully help others as well as I can. I also hope it engages other guys with more experience to also chime in and give redirection if it is needed so we all learn. I only ask a person to follow direction and report back with the findings as well as the fix whether my assistance was of help or not.

 

[RoushTang11]

To close the loop on this - it appears that the doors had NOTHING to do with the symptoms I was experiencing. The fittings that connect to the Condenser appeared to have a leak. The green dye was present outside on both upper and lower fittings. The fittings had some corrosion on them, they were cleaned and refitted. The system is now blowing ice cold and appears to be holding pressure.