Aircon Cold And Warm

[marinabrid]

Well    looks like i got many questions now i moved up in th world to a mk 2

 

after searching the forum i can't find the answer so here goes,

 

It has for sure got dual air con   its got vents above middle row and back row of seats and 2 sections on the control panel

 

the odd thing is  its blowing freezing cold at the front   but the middle and rear are both warm    like outdoor temp,  def not cold at all  no matter how i adjusted the temp setting down to low   the front stayed lovely and cold   but not the others.   whats going on     does it have 2 seperate sections that need regassing          

 

thanks 

[chromedome]

There is a unit behind the panel below the nearside rear window. This is why it has extra gas because of the two units. I'm not sure if it is a totally independent unit or if someone may have bypassed it for some reason.

 

No doubt someone on the forum will give more info.

 

Just to check, have you only got one rear window opening switch on the centre console?

[insanitybeard]

No, both the front and rear air con are powered by a single compressor, there aren't two separate systems. For that reason, if the front air con is working then so should the rear, unless you've got a dodgy climate control panel etc- just checking the obvious here, but you have dialled down the temperature setting on the right hand (rear) control on the panel? For maximum cooling both temperature settings should say 'LO'. Because the two systems are linked, you shouldn't be able to set the front and rear with a large difference in temperature anyway, if the rear isn't blowing cold when the display says it should be and the front blows cold with no problem then I can only think you've got a fault with either the climate control panel or the rear blower box or an actuator- e.g, the temperature control flap is jammed allowing warm air through. Might be worth checking for fault codes, the climate control panel can be interrogated with VAG-com.

[marinabrid]

yes   i made sure the settings were  low  on both   tried it on auto setting  then reduced the temp on each side.  the thing is blowing very loudly at the back when fan set to maximum  but just warm air   not even slightly chilly    i will plug the laptop in now and see if anything is logged   

[chromedome]

I wasn't sure if there was a condenser unit in there, that's what I meant by separate, wrong description on my part.

 

I get condensation drip from both front and back on mine.

[marinabrid]

on my vagcom  i don't see a climate control module     its version 311-2    if that makes a difference       is it called something else ?

[Bigjeeze]

Check that the fan is working on the rear section - also perhaps the flap motors are broken/jammed.

[insanitybeard]

Can't help with the VAG-com side of things I'm afraid, but in response to Chromedome's post above there is an evaporator matrix for the air con in the rear blower box.

[marinabrid]

found something on module called   cent. conv.   climatronic,   i  it says  fault code 00576 terminal 15,  07-10  signal to low     intermittent ,    does this mean anything to anyone,  from reading   the climate control should flash if faulty    mine doesn't flash on start up or anytime 

Edited July 2, 2014 by marinabrid

[chromedome]

Clear the fault code and see if it comes back.

[marinabrid]

another odd one,   went back to clear the code,  connected it up and   get message   no response from controller 

all the other controllers can be contacted      what a sod !  i tried reconnecting 10 times       will try again tomorrow  though i doubt if clearing the fault will make the rear cold  unless you know different 

[insanitybeard]

Clearing the code may not solve the issue, but it could be pointing to a defect with the climate control module itself. My aircon is degassed at the moment and non-functional, yet the control display never flashes, so just because it doesn't flash doesn't mean there isn't a fault. The fact that you were able to communicate with the module one minute but not the next could itself indicate a fault with the unit.

[marinabrid]

so  the code i got       any clues on what it means ?  00576 terminal 15,  07-10  signal to low     intermittent ,   

[gregers]

dunno if this will help at all?????

but irrc 'seatkid' posted up somewhere about clearing the dust/crud out from a vent somewhere on the front of the climate unit.

as said dunno if this will help but might be worth a hunt on here for the info.or if your really luckey and he sees it he will point you in the right direction.

[marinabrid]

had a good look but can't find any other members who have had the same problem,   could the climate unit be faulty and not send the cold air to the back   but send it to the front ?  or is it more likely something else    yet nothing else is putting a code up.

[marinabrid]

found this on the forum from silver beast written in 2012  

 

I was wrong about this, the wording in the handbook is confusing in that it says the Rear Air Con only works in "recirculate mode". It doesn't mean you have to set the system to recirculate mode, it means that the air in the rear compartment is drawn from inside the car prior to cooling not from outside. The front air-con (&heating) has the option of drawing the from outside through the Pollen Filter as normal or from inside when you press the recirulate switch.

 

how does air get drawn in to the system from inside ,  in that case is it ever going to be as cold as the front vents ?

[SilverBeast]

I think it draws the air in from the rear passenger compartment through the holes at the base of the left hand rear wheel inner cover. Sort of in line with the back of the middle row left hand rear seat where the feet of the third row left hand seat.  This then goes through the cooling evaporator matrix and is directed through the ducting in the left hand rear D pillar (behind the third row left hand top seatbelt mounting, which is why you don't get a nearside opening back window).  Further ducting takes the air to the roof vents.

 

I've never particularly checked the rear roof vent temperature.  To check it I close all the vents apart from in the middle of the dash, turn off the fan in the back and set the front to "LO".  It gets down to 6-8C air temperature from the middle vents, which is better than the mobile air-con man gets in his S-Max.

 

Things I suggest you check:-

(i) There are four pipes going to the back nearside wheel arch under the floor of the car. Two are for the heating and are the same diameter (they pass through the booster heater).  The other two are for the air-conditioning. From memory these are both narrower than the coolant pipes and one is narrower than the other.  With the airconditioning running I believe one should be cold and the other hot, though I have never checked the ones under the car. You can compare the temperatures with those under the bonnet at the front of the engine where the fill valves are.  If they are both the same temperature then I suspect it isn't operating as it should.

(ii) Air intake from the passenger compartment isn't blocked. I've never checked it does bring it in there as described above, it may come from inside the storage compartment in the left rear arch. I'd get the vaccum hose extension on it.

(iii) I believe the crud Gregers refers to coats the internal temperature sensor in the dash control module, again vacuuming the small slots wouldn't do any harm.  I believe there is a fan in there that can stop turning if it gets too much fluff in it.  I wouldn't expect this to be causing your problem though.

 

VAG-COM/VCDS see the controller as the Climatronic.  There is at least one temperature sensor in the compartment on the left of the rear compartment, but I believe you have to remove the panels to get at it.

[insanitybeard]

In theory it should be possible for the rear air con to discharge cooled air at the same temperature as the front system, because it is using air from inside the cabin which will have already passed through the front air con system on it's way into the vehicle. Or if the system is in recirculate mode the air should progressively cool as it repeatedly circulates within the vehicle and passes through both front and rear air con evaporators. Having said that, due to the number of vents in the roof that the rear air con supplies, it probably has a bit more work to do than the front.  

[marinabrid]

thanks for the info     i don't know where you get it !!!     i think I'm very lucky to have the front working at all and should be happy,   I've managed in the mk1 for 10 years with just the front and was happy enough, now I'm on our 1st mk2,   must say they are are very much more refined drive ,  i will check out the pipes under the car to see if one is hot and cold.  

Edited July 5, 2014 by marinabrid

[insanitybeard]

As for what that fault code means, you'd need a wiring diagram to check what the wire it is indicating a fault with affects, the

terminal it states is likely one of the multiplugs on the rear of the climate control module. The likely culprits will be

wiring faults, an internal issue with the control module or a fault with an actuator under the control of the module or a sensor

that the module uses a signal from. However, you need a wiring diagram for a pinpoint test.

[marinabrid]

May have found something here.     Reading the ford handbook   silver beast was correct in his 2012 statement,   on page 44  it states,    the rear air con   only operates in recirculated air mode,     i will try and test it when the weather is hot again,  there must be others out there with dual  who can confirm  their handbook states this also.

[SilverBeast]

Having looked at how the system works here i'm not convinced that the pipes will have a different temperature.  The ones I have checked in the engine bay are probably either side of the condenser.

 

I'll check mine next time I get to use the a/c in anger - I only have a 20min drive to/from work so it probably doesn't get into it's stride.

 

I did a trip from York to London and back to Otley (Leeds) earlier this week (average 51.1mpg!) to deliver my son's stuff to his flat, but as the car was loaded floor to ceiling from the back of the front seats to the hatch, I'm not sure it would have been a good test of the rear-aircon!

 

 

[marinabrid]

if you think about it     your description is correct,   the front air con    cools the air  for the front only,   if you want cold air from the roof vents  then you turn on recurculation mode and the cold air that is inside the car is then drawn in through the floor and sent out through the roof vents leading to a cooler car front and back   thats my theory  unless someone has a different one.

[SilverBeast]

Just been outside and checked by running car at tickover for less than 5 minutes.

 

Set aircon to auto and LO (by lowering front temperature setting as far as it will go). This sets it running permanently.

 

Closed all rear vents apart from middle row middle vent (so I can stick my hand in front of it from drivers seat).  The air temperature out of middle dash vent and rear middle row middle vent get to pretty much the same temperature.

 

The fatter of the two pipes under the car gets noticeably colder and the thinner one warms up.

 

I had the same confusion about the recirculate mode.  This just means that the rear cooling (and I believe the heating) always draws air from inside the car.  As I understand it front cooling (and heating) draw air from outside UNLESS the recirculate mode is selected, in which case it is drawn from within the car.

 

Mine will cool the front air temperature to below 8C at the centre vent if that is the only one open in the car and you leave it long enough.

Edited July 5, 2014 by SilverBeast

[marinabrid]

Looks like we have a full answer to the question and how the system works for those with dual air con.  Many thanks for your great help. one other question i have

 

i never had this climate control before so am unsure how it operates,

if i set auto  and the temp set is 22   which seems to be the factory setting   does the system automatically choose to use the air con  until the temp is down to the set  one  be it 22 or more or less.   then does it turn of the compressor when its not needed ,  i was just wondering if its simply best to turn it to  auto and leave it alone,  i dint want the compressor running all the time if not needed   but if it is only used  as and when  by the system  then i can leave it.