When I got the vehicle in summer it was clear that the aircon didnt work, VCDS showed the V71 pressure sensor open or closed circuit fault code, ordered a cheap Chinese replacement, waited ages, fitted it, same result, today fitted a more expensive one from a German seller and its reading the pressure, no more fault codes.

 

Trouble is its 12.5° outside and when I set the Climatronic to low thats what comes out of the vents, no cooler, is it simply because its not intended to turn the car into a deep freeze?

 

VCDS shows the pressure as 3.6 bar the compressor current as 0.815 amps I think and switching to econ drops the current to zero.

 

So I would say that everything is reacting as it should but the pressure on the high side does not increase so should the pump be working under these conditions, the fan is not engaging, VCDS shows a duty cycle of 9% maybe 10.5, I cant recall.

 

Do I have to wait for summer or see if it dehumidifies on a wet day?

 

Any advice, I recently bought a set of aircon test guages if that helps but I really need to know what it should be doing under the current circumstances and temperature.

 

Thankyou

To bump this back up, I hooked up the air con test guage set, ran the engine and set the Climatronic temperature to LOW, the pressure was the same in both the high and low pressure circuits at approx 50psi so the pump is turning, drawing current but not actually pumping, given that the outside temperature by then was around 10°c is this to be expected.

 

As per the thread title how can I test that the aircon is working in this cold weather?

 

VCDS is not showing any more fault codes on the HVAC module except the V71 airflow flap.

 

Am going to read the VAG self study guide to Climatronic tonight!!!!

from memory I think "inhibition" temp is 5'C   is the compressor a clutch type or constant speed/ variable flow?   this has a fail safe in the drive should the comp' seize up

Its the non clutch type and the make I think is Sanden (poor memory) its not the one with the shear plate where the spline strips out of the middle. It all appears to be turning and VCDS shows a compressor current of 800ma or so, not sure what current it is measuring though, only one electrical connector to the rear of the pump.

you could do a search for compressor shuttle or load valve they stick when not used which is why it's bad practice to not keep them well used,   ---'spect that's the current applied to the valve which I would reduce as the required load goes down,    someone correct if I'm wrong

Ok will do, more learning!

 

Still not sure if the aircon pump would be engaging in this cold weather, perhaps for dehumidification? the fans are not turning but again in this cold weather?

 

Maybe I could connect VCDS, look at the current drawn and if the valve is supposed to be working then I should expect a higher pressure in the second circuit, would that be correct?

If you look for the evaporator temp with VCDS or put a 99P thermometer in the vents you should still be able to prove that the air con is working at 10C ambient

Already used an IR thermo gun in the airflow outlets, air is at ambient temperature. Its so cold now I would not expect it to work.

 

I will wait for a hot day, springtime if need be, hook up VCDS, set to 16° and econ and should see no current on the valve if I understand how it works, then switch to auto and I should see current flow, if the air is still warm and the guages show no movement and I still have a reasonable low side pressure then I think I can be sure the valve has gone.

 

Will try to do a deal with the aircon place so they can evacuate the fluid (better than losing it as it costs a fortune) then recharge the next day after I have replaced the valve.