Good old HVAC actuators

[eisenhauer01]

Heat and AC has been acting up for a while now. Set the car to 72 and it blows hot, set it to 70 and it blows cold. I knew there was something up with the blend door actuators.
Plugged up forscan and checked for codes. Sure enough, drivers side, passenger side, and fresh air.
Went to the oscilloscope in forscan and only received errors when viewing the live data for those three door positions.
Fresh air door said "error" and the other two showed "100%" all the time even though I could make them move by changing the temp.
Ordered 3 new blend door actuators.
Removed the 3 actuators and took them apart.
Sure enough, all three had the same problem. Somewhere along the line, they over traveled which allows the internal positioning wiper to come off of it's potentiometer board, damaging the wipers when it reverses.
Pic below

Installed the three new actuators. Plugged them all up, and turned the ignition on. Hooked up forscan, cleared codes. Ran a FICM self test, no issues detected. Viewed the live FICM data, perfecto... 0% to 100% on driver's and passengers doors. Fresh air is working properly now as well.
We will see how long they last. It is a piss poor on the potentiometer side of these things.

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[GrabberBargeCaptain]

Whats involved in replacing the actuators?

 

[eisenhauer01]

Just 2 screws and a connector for each one. They are all pretty easy to get to.
The car does a full range cycle of them every time the ignition is turned on, so for that reason you want to make sure they are fully installed before turning the car on. In other words, don't plug them up and turn the car on with them dangling because they will over run their travel.
Also, on the driver's and passengers actuators, there are little intermediate gear pieces behind the motor that move a linkage arm. Make sure those are clocked correctly so the key and slot line up with each other. Didn't take pics for a full write up but most of the info is already out there.

 

[Garfy]

Whats involved in replacing the actuators?

Hopefully his 2015 and your 2023 are similar/identical in location placement, etc. otherwise it may not be so "easy". Sometimes manufacturers make things more difficult in newer model stuff.

 

[MexicanFiestaST]

I had to replace similar actuators on my 2013 Fiesta ST too soon(in my mind) after I purchased it new. This was a common problem reported in the Fiesta ST forums, with plenty of advice on how to diagnose and repair it(it was a real hassle in that vehicle, but not impossible), including part numbers.

I'm starting to feel like my Mustang is now starting to suffer similar problems, so it's interesting to see you having them also. Mine(2020) is much newer than yours, however, I have over 80k miles on it, now, and the HVAC is always running, except for those two short windows in spring and fall when I like having the windows down(Michigan, sigh). I don't yet have that "digital" problem like you(full hot or full cold), so I'm gonna wait it out until summer when the AC is needed see how it goes.

Thanks for posting the deconstructed pics!

 

[eisenhauer01]

If you have forscan, you can run a FICM self test and it will tell you for sure if you have anything out of whack, and which actuator is the problem. That's a quick and easy way to diagnose it. Also using the oscilloscope feature in the FICM module confirms if you don't see them moving between 0% and 100% when you actively change the temp enough to make it happen.

 

[Cobra Jet]

Heat and AC has been acting up for a while now. Set the car to 72 and it blows hot, set it to 70 and it blows cold. I knew there was something up with the blend door actuators.
Plugged up forscan and checked for codes. Sure enough, drivers side, passenger side, and fresh air.
Went to the oscilloscope in forscan and only received errors when viewing the live data for those three door positions.
Fresh air door said "error" and the other two showed "100%" all the time even though I could make them move by changing the temp.
Ordered 3 new blend door actuators.
Removed the 3 actuators and took them apart.
Sure enough, all three had the same problem. Somewhere along the line, they over traveled which allows the internal positioning wiper to come off of it's potentiometer board, damaging the wipers when it reverses.
Pic below

Installed the three new actuators. Plugged them all up, and turned the ignition on. Hooked up forscan, cleared codes. Ran a FICM self test, no issues detected. Viewed the live FICM data, perfecto... 0% to 100% on driver's and passengers doors. Fresh air is working properly now as well.
We will see how long they last. It is a piss poor on the potentiometer side of these things.

Is there any way to fix or prevent them from over traveling so it won’t “peel up” the metal part and destroy it as seen in your images?

What if the metal was mounted on the other side of the gear (in your posted images, to the right side) would that prevent the metal from being damaged if over traveled? My thought on that is, maybe whoever assembled the gear put the metal on the wrong side?

Can just the metal (copper?) be purchased to fix the problem instead of having to buy complete actuators?

 

[eisenhauer01]

Good questions. They crossed my mind as well.
This go around, I am going to give these a shot and see how long they last. They are cheap enough from Rock Auto. With that said, I have some ideas on it.
I thought about modeling up a piece and 3d printing it, so it gives a flat circular area for the wipers to ride on (in case they travel outside of the potentiometer section (board). The issue with that, is I don't know for sure if there is enough space between the two gears for any kind of material in there. Will investigate this further if these actuators crap out.
Theoretically, the wipers should NEVER over travel, as they home out to both limits when you start the car, and mechanically that should never allow them to over travel. How they do that, I am not sure. Possibly linkage allows for a little bit of overtravel depending on how hot or cold the plastic is maybe. When they are "homing out" in both directions, that should be happening while the wipers are in contact with the board the entire time, so it is a mechanical issue that allows the actuators to over travel, causing the wipers to fall off of the board.
A better design would have been to make the potentiometer board a full circle, so no matter what happens mechanically, falling off the board is not possible. But they were obviously trying to fit 10lbs of stuff in a 5lb bag with this design.

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