s3 air con not working

[armstrong_21490]

Well I just got my air con re-gassed today. The mechanic said there was no charge in it so there could be a leak. He attached the machine up and let it do its thing. Around 30 mins late it beeped. He did something to it and then 5 mins later it beeped again. He said everything was ok. no leaks and that it was charged up. Only problem was when we tried it the air con didn't work. He told me to get it scanned for fault codes cause sometimes if it has went completely flat this can happen. So when I got home I connected my car up to VCDS and there was no fault codes. If the ignition is on but not the engine the LED beside the AC comes on (like in the picture below) but if you start the engine the LED goes off after about 20 seconds and then if you press it it lights up but as soon as you remove your finger it goes out. Can anybody help me out at all?? Any help would be greatly appreciated.

here is the pic


Thanks

Ross

 

[S3 AEX]

Normally the light won't go out which means a fault and the air con will not take charge. If there's a fault the air con will not take full charge any way so your mechanic could be fobbing you off mate. When I tried re gassing mine it would only take a little charge and no more, it's normally the low pressure sensor that goes. I need to change mine, Audi's are one of the worst cars for air con problems.

 

[armstrong_21490]

He told me it was charged to 90% and to take it back to him tomorrow after I had cleared the code and got the AC to stay on to finish it off. I take it it doesn't bring up a fault code if its a dodge low pressure sensor?? Also when I turn my engine off the engine fans seem like they are working overtime and take a few seconds after the engines off to stop.

Ross

 

[Smirky]

When mine went it didn't bring up any fault codes either,but luckily the mobile air con bloke had seen it before took him couple mins to manually diagnose and he had found the problem 'pressure switch' must be common because he had a box of replacement switches in the van,

 

[Deze2014]

do your fans come on when your ignition is on but not the engine?

 

[armstrong_21490]

How hard a job is it to change the pressure switch?? Is it expensive??
When the ignition is on the engine fans don't come on no.

Ross

 

[Smirky]

No it's a cheap part ,it was under £100 for everything re gas switch

 

[armstrong_21490]

Well I left it for a week and a half and then last night I tried it again. The light by the button is now staying on but the air-con doesn't get cold. Has anyone got any ideas???

Cheers

Ross

 

[Smirky]

What light ?the Econ light?

 

[fouryoghurts]

Have u read out live data with vcds? Check everything's to spec.
Before swapping bits, you need to confirm the basics. Has the system definitely been charged with to correct amount of refrigerant? This system takes best part of a kg. unless ur AC guy knows what he's doing, I'd get the gas taken out and weighed, then recharged to spec, stick some gauges on it and see what's happening on both circuits.

 

[fangio]

Mine takes 540gms.....

 

[Chillout]

I don't think your guy would have fully charged it without running it as once the system equalises with the cylinder pressure he would have to run it to pull the suction pressure down to complete the charge

 

[fouryoghurts]

Yes, apologies, a nearer a half kg, not a kg. My bad. I think it's 525g +/- 25g...