Help. Air conditioning

fin199

Member
Hi,

my air con worked when i first got my car but has since stopped, I presumed all the gas leaked out
after some analysis i decided to replace the condenser and dryer.
it has now been re gassed and it passed the vacuum test, but on a hot day it wasnt working.

How would i find if its an ac compressor or electrical fault?
when the car is running i can actually feel that one ac pipe is slightly cooler than the other, implying that it is working but not properly? and when the engine is off the 2 pipes become the same tempature.

i don't think i can use a multi meter to diagnose this?
i cannot hear the compressor cutting in or out either... can you manually switch on the compressor with 2 cables??
 

RAB

Technical Specialist 1.2 TDI
You need a VCDS scan to tell you exactly what's wrong. It could be the compressor, pressure sensor, temperature sensor or even the cooling fan or controller that's causing the problem. The compressor does not switch on/off; it's running all the time.

RAB
 

Jeff Sutcliffe

A2OC Donor
Hi,

my air con worked when i first got my car but has since stopped, I presumed all the gas leaked out
after some analysis i decided to replace the condenser and dryer.
it has now been re gassed and it passed the vacuum test, but on a hot day it wasnt working.

How would i find if its an ac compressor or electrical fault?
when the car is running i can actually feel that one ac pipe is slightly cooler than the other, implying that it is working but not properly? and when the engine is off the 2 pipes become the same tempature.

i don't think i can use a multi meter to diagnose this?
i cannot hear the compressor cutting in or out either... can you manually switch on the compressor with 2 cables??
The most common reason for the air conditioning not working properly is the failure of one or both of the G65 and G263 sensors. I'm not an expert but @timmus scanned my A2 and diagnosed that that's why my air conditioning isn't working properly. One of the sensors is relatively easy to swap, the other one is officially only accessible after the dashboard has been removed but, in fact, can be reached by a contortionist from the driver's footwell. A scan will be required to establish where your problem lies.
 

fin199

Member
OK brilliant I'm getting it scanned in a little while so hopefully we will find something.

but the compressor does have a clutch, which engages and disengages the compressor
 

PlasticMac

Member
OK brilliant I'm getting it scanned in a little while so hopefully we will find something.

but the compressor does have a clutch, which engages and disengages the compressor
The compressor in the A2 has no clutch. It runs all the time the engine is running. The rate at which the refrigerant flows through the evaporator (and so cools the cabin) is controlled by a variable valve.
The scan will point you in the right direction.
When the system was re gassed, did this include checking the oil? If you loose gas, you loose lubricant too. The compressor and seals need to be lubed.
Mac.
 

spike

Well-Known Member
OK brilliant I'm getting it scanned in a little while so hopefully we will find something.

but the compressor does have a clutch, which engages and disengages the compressor
As indicated there is no 'on / off' clutch on the A2 aircon compressor. The pulley incorporates a 'failsafe' rubber isolator which deforms and allows the pulley to rotate if the compressor seizes to prevent the belt being thrown off and loosing the alternator drive

More details here


Cheers Spike
 

Jeff Sutcliffe

A2OC Donor
just got a scan done. G263 sensor open circuit/short with power
If that's the one where an Audi main dealer would take out the dashboard, search on here for the contortionist's method. You should also have the gas purged before you remove the bad sensor.
 

Proghound

Admin Team
G263 measures air output temperature to the vents, surely there's no need to purge the gas for that? I certainly didn't have it purged when Tom and I changed a dashboard on one of mine, and swapped out a dead G263 at the same time.
 

Jeff Sutcliffe

A2OC Donor
G263 measures air output temperature to the vents, surely there's no need to purge the gas for that? I certainly didn't have it purged when Tom and I changed a dashboard on one of mine, and swapped out a dead G263 at the same time.
Both sensors need replacing on mine and Tom told me that I would need to have the system purged before the job could be done. I, wrongly it seems, assumed that was the case with either sensor. Thanks for clearing that up.
 

RAB

Technical Specialist 1.2 TDI
Both sensors need replacing on mine and Tom told me that I would need to have the system purged before the job could be done. I, wrongly it seems, assumed that was the case with either sensor. Thanks for clearing that up.
Replacement of the G263 sensor and G65 high pressure sensor do not require the release of the refrigerant. The former is not connected to the refrigerant circuit. The latter's connection contains a valve that is closed when the sensor is removed, which re-opens when the sensor is re-fitted.

RAB
 

cheechy

A2OC Donor
For info @timmus / Tom was able to replace my G263 without dashboard removal. I tried it and couldnt do it - you need knowledge of how the sensor fits / where and combine that with small dextrous hands :)

Just for reference very few garages / people in the UK will know how to replace this sensor without dashboard removal.
 

depronman

A2OC Donor
For info @timmus / Tom was able to replace my G263 without dashboard removal. I tried it and couldnt do it - you need knowledge of how the sensor fits / where and combine that with small dextrous hands :)

Just for reference very few garages / people in the UK will know how to replace this sensor without dashboard removal.
You need hands the size of mice hands and triple jointed wrists. I doff my cap to Tom as he as indeed pioneered a way to change G263 with the dash in place on right hand drive cars
Some what easier on LH drive cars
I removed the G263 from a car with the dash out and it was not the easiest thing to get out so a nightmare with dash in car

Paul


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