Anatomy of the A2 climate unit

ajsellors

A2OC Donor
Introduction:

Recently I have needed to do work on the climate unit in my A2.
As I found certain information for right hand drive cars hard to find, I purchased the complete interior climate unit from a breakers. This allowed me to learn how it is put together, a task not possible with the dash and other interior components in the way in a car.

Below I will share the knowledge gained so that it may be of help to others.

Description:

The climate unit in the A2 is made out of a modular construction. The centre module, which contains the heating and cooling (with air conditioning) elements is almost identical for both RHD and LHD models. The air blower fan and pollen filter however are always located on the passenger side.

This picture shows the climate unit as would be seen from inside the car. The module is from an early car with digital control and air conditioning. The blower fan motor has previously been removed, but otherwise it is complete.

The digital controls monitor the air temperature entering in the inlet and also the air emitted from each of the outlets. The air temperature sensors can be seen by the grey plastic connector and the green and yellow wires.

The climate unit has 6 movable flaps controlled by 4 motors with built in positioning potentiometers.

The pollen filter is located between the blower fan and the main central section. This is changed from inside the car through an opening flap below the glovebox on the passenger side. Unlike some other models which fit the filter on the external fresh air intake, the air in the A2 is always filtered, even in recirculation mode.

The lower module of the central section contains the heating and cooling elements. The engine cooling system driven heater element is fitted above the air conditioning cooling element. The electric auxiliary heater is also fitted here where applicable.

A2 air con 001.jpg

This picture shows a view not normally seen as this is the side facing the engine.

The fresh air is drawn from the opening slats in the top of the bonnet.

The higher flange attaches to pipes running to the engine’s cooling system to drive the heating element. The lower metal pipes contain the air conditioning refrigerant.

The rubber hose allows any water condensed off the cooling element to run away. This is deposited below the car on the ground.

A2 air con 002.jpg

The right hand (RHD driver’s) side of the central module contains the V70 central flap positioning motor and the G263 evaporator outlet temperature sensor. The latter is the major difference on the central module between LHD and RHD cars in that the G263 sensor is always positioned on the driver’s side. The other flap motors attached to the side of the central module are always in the same position.

The outlet temperature probe can be seen in the driver’s footwell airflow outlet. It is the green flat circuit board.

The V70 central flap motor is fixed by a bracket held by two pins which fit into holes and a single clip. The one motor drives the position of both the flap which controls the front and rear footwell airflow and also the vents on the front of the dash.

A2 air con 003.jpg

The motor drives the flaps with linkages that run in shaped grooves on the motor’s drive wheel. The shape of the grooves allow the alternate and combined opening and closing of the two flaps with one motor.

A2 air con 004.jpg

A2 air con 005.jpg

On the RHD car, the G263 sensor is above and in front of the V70 motor.
The sensor itself can be removed easily by pulling out. Gaining access to pull is the hard part!

A2 air con 006.jpg

The V107 windscreen demister and V68 temperature control motors are located on the left (RHD passenger side) of the central module.

A2 air con 007.jpg

Both motors are held in a single bracket with two pins which fit into holes and two clips.

A2 air con 008.jpg
 
The demister and temperature control flaps are driven by toothed gear wheels. When removing these motors, it is important to realign the mating gears in the correct position.

A2 air con 009.jpg

Like all the flap control motors, the design and applicable parts altered for 2004 MY and later cars. The earlier and later motors have different electrical connectors and are not interchangeable.
The picture shows the early motors on the left and a temperature flap motor from a 2004 MY car on the right for comparison.
The later motor design has fewer gear teeth which makes alignment easier. The later motor can be realigned by feel as the last teeth of both wheels match up at the very end of travel.
By comparison, the earlier motor design’s teeth extend further so it is only possible to align the gears visually.

A2 air con 010.jpg

The demister and temperature flap gears have corresponding unique alignment teeth which must be positioned together between the motor and flap gears to ensure correct operation.

A2 air con 011.jpg

The temperature flap controls the control of how much heated and unheated air enters the cabin. With the digital controls, this motor adjusts the airflow to maximise the heating speed. When the engine is cold, if the set temperature requires the addition of heat to warm the car up, the flap will be on the full heating position until the car nears the desired temperature. Turning the climate control up far above the intended interior temperature will not speed up the warming of the car.

A2 air con 012.jpg

The V113 recirculation flap motor on the left (of a RHD car) of the blower flan controls the pair of flaps that determine the source of air entering the climate unit.
In the normal position, the exterior flap is open and the interior flap is closed. Air is drawn in from outside. When the control is placed in the recirculation mode, the positions of the flaps reverse, closing off the exterior flap and opening the interior flap.

A2 air con 013.jpg

In recirculation mode, air is now drawn in through the vents below the glove box. Turning on recirculation also automatically enables the air conditioning cooler if in ECO mode as this prevents the windows from misting up.

A2 air con 014.jpg

The top of the central module connects to the windscreen demister outlet and ducts in the dash which direct air to the 4 vents.
The central two vents and the side vents are supplied independently by 3 outlets. The central outlet drives the vents above the cup holders and the side outlets are ducted to the vents at each end of the dash.

When the vent flap is closed, the shape of the side vent flaps actually allow a small amount of air to continue to flow. This keeps airflow running to the side window demister vents.

A2 air con 015.jpg

The drive from the central flap motor doesn’t open the vent flaps fully unless the footwell flaps are closed as well.

A2 air con 016.jpg


Tips:

When the vent button is pressed on the climate control, I find the airflow poor unless all other air outlets are closed.
The best compromise in hot weather I have found is to have the footwell and vent flaps open and the windscreen flap closed. This give good cooling to the lower body and the face whereas opening the windscreen demister flap robs the face vents of airflow.


The recirculation, temperature and demister flap motors can be accessed for removal and replacement by only removing the glove box.

http://www.a2oc.net/forum/showthrea...t-control-and-windscreen-demister-flap-motors


The central flap motor and G263 evaporator outlet temperature sensor can be accessed for removal and replacement by only removing the trim panel below the steering column. It is not necessary to remove the dash to replace the G263 sensor, although it is a more fiddly if less complex and time consuming job.

http://www.a2oc.net/forum/showthrea...-temperature-sender-without-removing-the-dash
 
Fantastic write up and hopefully some help to many members ( me amongst them) who have some gremlins with the climate control. Thread has been 'sticky' for easy future reference :)
 
Picture of the recirculation flap motor in its mounting bracket showing the drive plate.

A2 air con 017.jpg

This is probably the easiest one to change. Access is by removing the glove box and the motor is on the end of the climate unit to the left side of the blower fan (on RHD). The bracket is clipped in place on the top and held at the front and below with two Phillips screws.
 
Forum members fequently comment on how they continue to discover something new on their A2. I have been trawling the furum for over 12 months now and still discover new 'features' of the A2 This thread on the climate control does notmention it but the post

http://www.a2oc.net/forum/showthread.php?3512-Essential-facts-tips-amp-tricks

Does. Am I the only one who did not know that the climate control settings are stored with the ignition key?
So each driver has its own personalised setting when they turn the ignition on. Maybe my last Audi had this and I never knew.

Any long term forum members out there who had not discovered this or am I out on my own?
 
Any long term forum members out there who had not discovered this or am I out on my own?

I have to admit that I did know that one already, but I only found out a few months ago after 13 years of A2 ownership.

It is one of those things that are not that well known though and I am sure that you have added another "I never knew that" to many members.

And you are very right, there are lots of little things about theA2 that surprise me, even after all of these years of ownership.


Cheers
Steve B
 
Nope I didn't know that one - are any other car settings stored within the key (e.g. radio volume?)? I guess the A2 is too old to have had things like (electric) seat and mirror positions stored on the key too?
 
Nope I didn't know that one - are any other car settings stored within the key (e.g. radio volume?)? I guess the A2 is too old to have had things like (electric) seat and mirror positions stored on the key too?

As far as I know it is just the Climate settings (no memory on the mirrors and no electrically operated seat rails so unfortunately that nice feature, which is extremely useful, is not an option) Haven't noticed the radio volume, it would be nice but I don't think it does?

Steve B
 
Hello from Slovenia!

I love this forum :) you helped me fix most of my A2 bugs :p but there is one unsolved...can someone help?
So...my drivers side vent jet is cooling much colder than center vent jet, and muuuuch muuuuch colder than passenger vent jet. Passenger vent jet is actually heating the car when drivers side is cooling it. And the center vents are somewhere in the middle. What could be wrong? If i set the temp from LO to HI, the temerature changes on all the vent jets, but the drivers side is always blowing colder than passengers side. Is there a way to fix this?

Best regards!

Sebastijan
 
Excellent write up Thank you! Just a small point though the heater rad should be the bottom in your picture A2 Air Con 002 picture.


Sarge
 
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