C4 Picasso 2017 Hot Air Only on Driver Side

Post your Cit/Peu/Ren air conditioning queries or advice.

Moderator: RichardW

chrisnasulea
Donor 2022
Posts: 6
Joined: 10 Jan 2022, 10:55

C4 Picasso 2017 Hot Air Only on Driver Side

Post by chrisnasulea »

Hi everyone,

I'm very happy to have found this forum! I seem to be having the same problem Janko was describing in this post: viewtopic.php?t=64206
With the heating turned all the way up on both sides I only get hot air on the driver's side. On the passenger's side the air coming in feels like outside air - cold, winter air.

So, I assume the heater matrix is all clogged up and needs replacing. Can you please help me with a suitable part number for my VIN: VF7**************[VIN obfuscated, can be read by forum staff]

I'm also including two pictures of the dashboard as I've seen Picassos with very different layouts on YouTube.

Thank you,

Chris
Attachments
WhatsApp Image 2022-01-10 at 12.05.18 PM (2).jpeg
WhatsApp Image 2022-01-10 at 12.05.18 PM (1).jpeg
Online
Hell Razor5543
Donor 2021
Posts: 12488
Joined: 01 Apr 2012, 09:47
x 1674

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by Hell Razor5543 »

Hi, and :welc: to the forum. It is likely that a flap control has failed for some reason. It looks like your C4P has dual zone climate control. There are flaps that manage the air flow for each side, and if the 'heat' flap stops working on one side that side can no longer adjust the air temperature. It is very unlikely the heater matrix is blocked, as it is used to provide the initial heat for both sides.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

This vehicle does NOT have dual zone A/C. It is simply regulated for the whole vehicle, hence why there is only one heating control on the touch screen.

The heater matrix can become blocked on one side which can cause this, or it may well be the air mixing or air distribution. Before you go any further, it may well be worth getting a diagnostic first to determine the causes or at least try and rule out the electrical issue.
RichardW
Forum Treasurer
Posts: 9920
Joined: 07 Aug 2002, 17:12
x 564

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by RichardW »

GiveMeABreak wrote:
10 Jan 2022, 14:14
This vehicle does NOT have dual zone A/C. It is simply regulated for the whole vehicle, hence why there is only one heating control on the touch screen.
It does... see the first photo where there are separate temperature scales on the left and right of the screen.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

I think I had 2 other vehicles on servicebox :roll: and it hadn't cleared the previous one, so yes, I stand corrected James, post amended, thanks Richard.
RichardW
Forum Treasurer
Posts: 9920
Joined: 07 Aug 2002, 17:12
x 564

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by RichardW »

It might not have separate for the rear, but the front definitely is
chrisnasulea
Donor 2022
Posts: 6
Joined: 10 Jan 2022, 10:55

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by chrisnasulea »

Thank you everyone for your input!

I am going to take the car to a friend's garage in the morning to hook it up to a tester and see if there's any information about failing servos or other electrical issues.

We're probably also going to search for the passenger side hot air flap to see what state it's in. If you have any suggestions as to where that flap might be it will be greatly appreciated. He may already know where to look but more info is always better than less info.

Thanks,

Chris
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

I'm afraid it's not that simple if you are going down that road Chris. The flaps are controlled by stepper motors (5) for both the air distribution and air mixing on each side. The 'flaps' are driven by the motors using control rods (14):
C4 Flaps.JPG
Getting to the main heater unit / evaporator is a fascia removal (dash out job). There are some components you may be able to get to by removing either side of the footwell panel trims.
chrisnasulea
Donor 2022
Posts: 6
Joined: 10 Jan 2022, 10:55

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by chrisnasulea »

It sounds expensive. :)

We won't be removing any dashboards tomorrow. I can't imagine the plastic surviving the procedure in our current sub-zero temperatures without access to a heated garage.

I'll come back here and post some updated info after we have a look at whatever error codes may be showing on the tester.
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

The only downside to testing is that it can only show whether the flap motors are operating or not - I don't believe it can show if the flap is physically moving as that's a mechanical gearing issue. So although the motor spindles may be operating, that won't help if the spindle gears are worn.

When did you last have the coolant system drained and refilled? That may be worth looking at first and if there is a blockage in the heater core they can sometimes force it out via the matrix water pipes when flushing the system through. Worst case scenario is you end up with new coolant and a clean system. If that doesn't sort it then you can investigate further.
chrisnasulea
Donor 2022
Posts: 6
Joined: 10 Jan 2022, 10:55

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by chrisnasulea »

Hello again,

No error codes were found using the tester.

We opened the panels under the glove compartment and found a part had broken off from the heating unit. I've circled the place where it used to be attached in the 1st picture in red.
IMG_20220112_135855.jpg
IMG_20220112_135902.jpg
IMG_20220112_135629_red.jpg
I've left the car at my friend's garage and he will try to improvise something to either reattach it or to at least force it to be stuck in the hot position instead of being stuck in the cold position.

Does anyone happen to have access to the instructions for the replacement of the heating unit?

Thanks,

Chris
User avatar
mickthemaverick
Donor 2022
Posts: 9246
Joined: 11 May 2019, 17:56
x 2504

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by mickthemaverick »

Hi Chris,
You may find this video helpful from a similar vehicle :)

User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

@ Mick - Mick those are completely different systems to the C4 Picasso (B78). That 407 does not have the same mechanism at all :wink:

chrisnasulea wrote:
12 Jan 2022, 18:41
Hello again,

No error codes were found using the tester.

We opened the panels under the glove compartment and found a part had broken off from the heating unit. I've circled the place where it used to be attached in the 1st picture in red.

I've left the car at my friend's garage and he will try to improvise something to either reattach it or to at least force it to be stuck in the hot position instead of being stuck in the cold position.

Does anyone happen to have access to the instructions for the replacement of the heating unit?

Thanks,

Chris
It's a fascia off to get the heating unit out. Those control arms are on the diagram item (14) that I mentioned earlier.

Item (14) is the Air Conditioning Control Kit, part number: 9821297680, available from Citroen, priced (UK Sterling £112.64).
User avatar
mickthemaverick
Donor 2022
Posts: 9246
Joined: 11 May 2019, 17:56
x 2504

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by mickthemaverick »

GiveMeABreak wrote:
12 Jan 2022, 19:21
@ Mick - Mick those are completely different systems to the C4 Picasso (B78). That 407 does not have the same mechanism at all :wink:

It's a fascia off to get the heating unit out. Those control arms are on the diagram item (14) that I mentioned earlier.

Item (14) is the Air Conditioning Control Kit, part number: 9821297680, available from Citroen, priced (UK Sterling £112.64).
Fair enough Marc, I thought there were similarities in the flap mechanisms which may have been helpful but obviously not!! I stand corrected! :)
User avatar
GiveMeABreak
Forum Admin Team
Posts: 28508
Joined: 15 Sep 2015, 19:38
x 3486

Re: C4 Picasso 2017 Hot Air Only on Driver Side

Post by GiveMeABreak »

No worries, these Picasso ones are a bit more Carlos Fandango-designed with the long control arms that seem to be brittle by the looks of it.