Weird A/C problems in my Citroën C4 Picasso

[Steguit]

Good evening everyone.
I'm writing to you about a problem that's been bothering me for some time on my 2007 C4 Picasso (mk1), with a 1.6 HDi.
I should start by saying that I'm Italian, so I drive on the left side of the car.

For about a year, I've had the infamous problem of hot air always blowing from the passenger side.
I immediately went to check the flaps, which were breaking along with their gears, and noticed that (strangely) everything was fine.
So I decided to remove the actuator to keep the air always cold (since it was the middle of summer and I had to go on a trip), but also because I wanted to buy Diagbox.

Lately, the car has started doing crazy things, like blowing air out of the footwell vents (even though it's set to the upper vents), or when I raised the temperature on the driver's side, the fans on that side would turn off until the maximum temperature was reached (which, if I'm not mistaken, is 28° Celsius).

I decided to buy Diagbox and run a thorough scan; the result was error F72E - "Front right mixing motor fault."
With such clear evidence, I immediately decided to buy a new motor, identical to the original, namely the DENSO DAT21004.

I wish I'd never done that. In addition to error F72E, I also received error F766 - "Failure to communicate with stepper motors (LIN network)" - as well as numerous fan motor faults, which I managed to clear.

Since I had the diagbox, I decided to retrace my steps, checking both the motor and everything that came before it.
I installed the old actuator: I tested the left and right screen buttons for temperature control (the control unit receives input from both screens), I tested the fan motors (positive results here too); I tested the actuators, both the old one and the newly purchased one, and the result was that they didn't move, even when disconnected from the flaps. I tried helping them turn by hand (obviously without using too much force), but to no avail; they were both incredibly hard to turn, both with and without the connector.

Now, first of all, I want to apologize for the long post, but I'd like to ask if anyone has any advice or suggestions regarding this situation.

I think everything else that happens around here (the fans turning off when the temperature rises, or the air being blown somewhere other than the one in the screen) is caused solely by the F72E code, especially since I've only had that one when looking at past reports using diagbox.
Am I wrong?

The thing that drives me crazy is that (after locking, unlocking, and getting back into the car), when I turn on the ignition, the actuator searches for the limit switches, then moves up and down, but from that point on, it doesn't want to move at all.

I'll conclude by thanking whoever replies and wishing you a good start to the week.

[mickthemaverick]

To have the best chance of some help post up the car's year, engine and gearbox details with the RPO number.

[Steguit]

I apologize for not responding in time, but I didn't have the car available.
I have no idea what an RPO number is. I searched the forum and from what I understand, it's one of those numbers.
I apologize and thank you again.

[mickthemaverick]

Yes the RPO number is 11218. It is needed to get the correct information from the Stellantis database for your car. I can only try and find the diagram for the heater control circuits which I will do in the morning as I cannot get on my system at this time.

[PaulC5]

The rpo number (production date code) is 11218FV with the fv being the factory. Giving 27 July 2007 and the Vigo factory in Spain http://www.citroen-ds-id.com/gen/Gen_Organr.html

EZRC is the paint code so grey aluminium.

[mickthemaverick]

I had a quick window, hope this helps:

ac diagram.pdf

copied from Sedre backup

(853.84 KiB) Downloaded 97 times

[Steguit]

Thanks to both of you for your help, I'll check this diagram right away and see if I can find the problem.

[mickthemaverick]

You may find the information in the following link helpful in decyphering the diagram: viewtopic.php?t=80489