non working aircon

[caldirun]

Any advice on aircon fault finding, please

[Imran]

Quickest and easiest thing is to use VAGCOM and see if it shows up any errors. If you can borrow some ones or see if someone local to you has the software and the lead.

Where are you based? What happens when you put aircon on? any messages on the aircon display? you get hot air? cold air? anything?

[Eshrules]

Any advice on aircon fault finding, please

I think you'll find few can help with such little description of the fault.

please give us some details on what's happened so far and what you've done....

[caldirun]

Quickest and easiest thing is to use VAGCOM and see if it shows up any errors. If you can borrow some ones or see if someone local to you has the software and the lead.

Where are you based? What happens when you put aircon on? any messages on the aircon display? you get hot air? cold air? anything?
Thanks Imran, its not the Heating/Ventillating side of the HVAC thats at fault, its the AC side, i.e. when its supposed to blow cold air, its not cold air that blows out.
I have checked the condensor cooling fan on the front of the car and it is running, air is blowing through the evaporator but no heat transfer, I am assuming loss of refridgerant/ knackered compressor, just wanted some fault finding ideas (how do you check for refridgerant volume and pressure, how do you check compressor function?) from someone with more experience on AC.
I do have Vag-Com if you can tell me what to look for, will it give refridgerant pressure/volume readings?, cant seem to find them.

[Imran]

Plug in vagcom and I THINK its 08 AutoHVAC, check for any error codes, see what comes up, and post the results. Has the aircon been regassed? do you know when it was last regassed?

[caldirun]

Plug in vagcom and I THINK its 08 AutoHVAC, check for any error codes, see what comes up, and post the results. Has the aircon been regassed? do you know when it was last regassed?
Only error code is V71 the old air flap actuator problem, just recirc not working, dont know about regassing only had the car since October.

[caldirun]

Only error code is V71 the old air flap actuator problem, just recirc not working, dont know about regassing only had the car since October.
Is re-gassing the only way to check, its £80 down the drain if there is a problem and it has to be vented to work on it!
Has any member some knowledge of air con fault finding?

[caldirun]

Is re-gassing the only way to check, its £80 down the drain if there is a problem and it has to be vented to work on it!
Has any member some knowledge of air con fault finding?
I have checked HVAC measuring blocks 1 and 8. Group 1 A/C clutch sw-off cond 1-12. gives (in Auto)0 and (in Eccon)6.
Group 8 Voltage A/C clutch remains at 14V.
The pulley is turning but the boss on the radiator side (front of pulley) is not turning, should this turn when clutch is energised. Should the measured voltage change between 0v and 14V, if so what could the problem be?
Where is the clutch relay located and what does it look like. Is there a connector at the front which can become unseated?
The A/C pipes going into the bulkhead do not cool but are pressurised, I tried pressing the valve pins in.
Any ideas much apprieciated.

[caldirun]

I have checked HVAC measuring blocks 1 and 8. Group 1 A/C clutch sw-off cond 1-12. gives (in Auto)0 and (in Eccon)6.
Group 8 Voltage A/C clutch remains at 14V.
The pulley is turning but the boss on the radiator side (front of pulley) is not turning, should this turn when clutch is energised. Should the measured voltage change between 0v and 14V, if so what could the problem be?
Where is the clutch relay located and what does it look like. Is there a connector at the front which can become unseated?
The A/C pipes going into the bulkhead do not cool but are pressurised, I tried pressing the valve pins in.
Any ideas much apprieciated.
Had a good look today, connector on power steering reservior bracket had become disconnected, hence no voltage across clutch winding, no errors on VagCom, no voltage drop shown when clutch was energised (now drops .4V as show in measuring blocks).
Now blows icy cold, for the first time since I bought it 6 months ago.
Is it worth doing a "How to" guide on aircon fault finding as it appears no one knows much about this aspect of the Passat? let me know

[snapdragon]

How daft that that doesn't give a fault code! I assume the clutch on the front of the pulley now rotates when engaged? It sounds like the electromagnetic clutch plate that pulls in onto the rotating pulley, thus spinning the compressor via a shaft through the middle of the pulley.