C5 Aircon /heater flap known issues.
  • Register
  • Help
Results 1 to 5 of 5
  1. #1
    1000+ Posts George 1/8th's Avatar
    Join Date
    Dec 2003
    Location
    Melbourne, Victoria.
    Posts
    1,389

    Default C5 Aircon /heater flap known issues.

    Hi Froggers,
    I've now had my C5 for 2 years. It's the petrol V6 with the ZF - 4HP20 auto. It's been the greatest Citroen I've had so far, in spite of the usual things these cars can do.
    Not long after I bought it the car presented with the faulty Air con issue. I looked into the problem with alacrity because it was very uncomfortable to have cool air on one side and FULL HEAT on the pasenger side on a hot day.
    I obviously didn't look quite far enough into the issue at the time because all the info I could find then related to Citroen PSA producing a kind of control motor shaft extension kit, which when fitted made sure the set position of the heat control flap did was it should.
    This is what happens, the extension kit can be a fix in many cases, but it's only a temporary fix. It can create a worse problem.
    The climate control design means that the heater module and cooling module are both fully and permanently operating at all times. The only factor which controls air flow through them is a few computer controlled air control flaps. The designers never factored stress into the equasion, so they didnt use chopper/ sensors for flap positioning information. The climate control computer only knows where the flaps are by their end positions. When the motors are working and the flap comes to it's end position, the amps in the motor spike. This takes a moment. While this is happening , a huge amount of stress is applied to the flap structure and shaft. This can eventually snap, so all control over it's position is lost from that point.
    This is a far worse event than just a control motor to flap shaft issue. It typically means the entire dash has to come out, to access the climate control box. Then the removal of that to service it and change parts. The problem with that is you'd have to disconnect heater hoses and open up the aircon pipes and lose the aircon gas etc etc.
    No friggin way Jose.
    Clever European owners figured it would be way easier to remove the glovebox and the stepping motor and then cut off the side of the climate unit with a hacksaw. Pull out the broken flap assembly, rebuild or replace that, then refit the side of the box..Glue or plastic weld it all back together. Job done in a couple of hours.
    I think I'll be practising on a C5 at the wreckers. There are many examples to see on youtube.
    Good luck fellow C5 owners.
    BTW.... This is a common problem in many European cars, obviously Peugeot, but also some Renault and more importantly many Mercedes Benz, and BMW models and many more. It's not just a Citroen or a C5 thing.

    Advertisement
    Last edited by George 1/8th; 13th December 2016 at 12:16 PM.

  2. #2
    1000+ Posts George 1/8th's Avatar
    Join Date
    Dec 2003
    Location
    Melbourne, Victoria.
    Posts
    1,389

    Default

    A small update. Today I removed the glovebox, removed the upper control motor of the two on the left side of the climate unit. I tested the flap shaft with a large screwdriver so I could rotate that spindle quickly. It all worked and moved as you would expect, no sign of any disconnect between the turning of the spindle and the control flaps. I did find that the new splint I made and fitted yesterday had already failed and was now useless. So I replaced that and now all appears to be working as it should. So it appears in the case of my C5, the problem so far hasn't been caused by a breaking flap shaft. It's just been all in the spline connection. I also found that the climate unit is different to each and every one I've seen on youtube.

  3. #3
    Fellow Frogger
    Join Date
    Jan 2004
    Location
    Sydney
    Posts
    9,777

    Default

    Yes, the flap motors are geared up and run until they stall at the end of travel as you say. The factory fix was to double the length of the drive peg as a snap in part on the same motor. The motors do not give trouble, but you could never buy just the longer peg and it was only ever supplied with a new motor unit. I made a couple longer pegs out of cast plastic resin not accounting for the torque involved and they ended up twisted and sheared off. What you say makes sense, so it's a bit of a design failure.

  4. #4
    1000+ Posts George 1/8th's Avatar
    Join Date
    Dec 2003
    Location
    Melbourne, Victoria.
    Posts
    1,389

    Default

    Hi David I agree. They did a couple of things wrong. The little motors are great. The plastic they make the flaps from is not a good enough grade to take the strain. The splines can split open, so you lose traction. The shafts can just break off. Luckily mine haven't done that.
    Many different breeds of vehicle have this same problem.
    I ended up making the peg out of carved tasmanian oak dowel, and strengthened it with 5 minute araldite. If this fails I'll try solid aluminium strap, hand filed to the right shape and size.

  5. #5
    Fellow Frogger! Balki's Avatar
    Join Date
    Nov 2010
    Location
    Sheffield/Tasmania
    Posts
    625

    Default

    there is a new motor avaiable from germany with a shaf twice the length, i have fitted a dozen of these and customers have never returned with the same product
    2016 Cactus
    2003 Range rover l322
    1974 D special
    1971 D special
    1992 CX TGE Safari
    1961 ID19
    1972 DS21 Safari
    1965 Renault R4
    1923 Citroen B2
    1927 B14
    Massey ferguson 550

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •